Hi,
I should probably pre-warn you this is likely to be a long message.
It’s hard to know where to start, 
my dad & I aren’t close, this is actually for a number of reasons, growing up he was never around, always working, or at the pub, or in his shed, he was just always somewhere else, when he was around, he was usually drinking, or arguing with my mom because of his drinking. Because of this, I have literally NO happy memories of him, I mean, like none, at all! Looking back, I can see now how much my mom was protecting us from how bullying & spiteful & petulant he is. There were a number of incidents with his drinking over the years, the ones that stand out most, one Christmas eve my sister cooked us all a special dinner, & she put so much work & effort into it, finding recipes we’d all like, did all the cooking herself, & dad got drunk, didn’t eat any of it, was practically falling asleep in his dinner, & just wrecked the whole thing, I felt so sorry for my sister, for the effort she’d gone to, … There are no words. Then there was the night before my 18th birthday, I had gone to bed slightly early, I could hear my mom downstairs, telling my dad not to drink so much, which mom & my sister were blowing up balloons, & putting up birthday banners, on the morning of my birthday, he had a hangover, I saw the empty wine bottles, this hung like a cloud over my birthday, while my mom still tried to pretend it was special. There was a load of Christmas’s, birthdays, & holidays where we ended up tiptoeing around him because of his drinking, 
. January after my uncle (dad’s brother,) passed, I don’t even know what it was about, all I know is that he yelled at me to the point I ran to my room in tears, totally freaking out, I called my mom, (she was babysitting at my sister’s house at the time,) she said to keep the door locked & she would be back as quick as she could, meanwhile downstairs my dad put on music & turned it up really loud, I was terrified. When mom got back, she turned the music off & came up to check on me, dad had put the music on, turned it up, then gone down to the pub, leaving it blaring and me terrified. My mom tried to call him, partly trying to find out where he was, partly trying to find out what was going on, mom wouldn’t repeat to me what he’d said, but just said he was drunk, & mouthing off, then dad started sending her texts slagging me off 
. Mom called my sister & explained to her, they picked mom up & went looking for dad, they found him, he was about to get into his car to drive home, he was so drunk he couldn’t even walk straight 
, gladly they got his keys off him, & took him to my uncles house, mom stayed with him there, but called me to let me know what was happening.
June 2020 mom collapsed and was diagnosed with a brain tumor, during the month or 2 after this, there was a bad incident, they were in the kitchen arguing about his drinking, & his petulant behaviour, the argument ended with dad throwing down a wine bottle smashing it on the kitchen floor, & saying aggressively, “AND YOU CAN CLEAN THAT UP AS WELL WHILE YOU’RE AT IT!” Then stormed out to the pub , my poor mom, she was terminally ill with a brain tumor, & he was treating her like that, 
I helped her clean up the broken glass. We had to care for mom at home because of COVID, what can I say, more drinking, more arguments, more temper tantrums. January 2021, there was an argument that got so bad I ended up cutting my wrists. Mom was trying to find the bottles to pore them out, she’d snuck out while he was drunk asleep, & found he’d hid a now nearly empty litre bottle of vodka in the recycling boxes outside, she pored out what was left, this is what had started the argument the next morning, he’d found the bottle was empty. My poor mom, I will never forget the look on her face when she walked into my room & found me, despite the tumors causing her to muddle her words, she managed to call me an ambulance.
Looking after mom, it was traumatic watching her deteriorate, it was horrendous watching dad yell at her & berate her, & humiliate her, while she was too ill to defend herself, too ill to even be able to string a coherent sentence together , he would get drunk, & make the most disgusting jokes about how he would “dance on her grave after she’s dead,” & the like. Mom passed April 2021.
He continued to drink, pretty much all day every day at this point, & would often repeat the same prattling drivel over & over again. One incident he repeated several times, about when he was younger, before he met my mom, an incident she’d never known about. He had gone drinking with friends, & he was talking with the barmaid at the bar, a man came & interrupted his conversation with the barmaid, dad said “we’ll sort this out later,” by his account, he found the guy in the parking lot & decked him sending him flying, I honestly don’t know what disgusts me more about this, the fact that my dad hit that poor man like the mindless, bullying, neanderthal he is, or the fact that he actually thought it was ok to brag about it, 
.
Boxing day 2022, he got drunk, argued with his new girlfriend on the phone, I turned off the phone thinking it best he sleep it off & talk to her when he’s sober, I went to bed, was woken about 2 hours later by him put the TV on & turned it right up, when I asked him to turn it down, he yelled at me, to the point I ran to my room in tears, I was terrified & alone. Meanwhile, downstairs, dad knocked stuff over, messed up the room, then threw down the Christmas present I’d got him & stamped on it. The next morning, no surprise dad was being sick, & very hungover, he asked for a glass of water which I got him, he asked for some toast, which I got for him, but yet when his girlfriend called, when he said he felt rough, she said it served him right, he said he wasn’t getting any sympathy from me in such a way as to imply I was moody with him, but I hadn’t even said anything, I hadn’t been moody in any way, he was just using me to subdue her, so she wouldn’t moan at him making her think I had, , then within about 20 minutes he was changed, had a shower & out the door. I was left scared, traumatized, depressed to the point of suicidal, & alone. He didn’t come back to the house that night, & he didn’t call to say he was staying at her house, though I know that’s where he was. The next day I didn’t feel any better, so I got an emergency appointment at the doctor’s, I told them all about it, & I was due to spend new years at my boyfriends, the doctor suggested I call & ask if I could go to my boyfriend’s (he lives with his parents) early, so that’s what I did, I called, & gladly they said pack a bag & come straight over. My boyfriend & his mom have been amazing. Sadly last year didn’t get any better, dad stressed me out of my skull, it was bad enough that I attempted suicide, twice! & ended up in hospital both times.
This brings me to my current dilemma, as I say, there’s no love lost between me & my dad, we have never been close, & as far as I’m concerned, never will be close, but I have reason to believe that his current girlfriend is using him, playing mind games with him to keep control of him. When they were first going out, she kept accusing him of looking at other women, I know this is something he would never do, he’s just not like that, but I could see how he was using the accusations to control him, the more she accused him, the more he would panda to her, trying to get her to believe him that he would never do that, he would show her his phone trying to prove he wasn’t seeing anyone else, she had him call her ever hour or 2 to say where he was, who he was with, what he was doing, till eventually, he’s practically moved in with her, he doesn’t leave her sight, she’s controlling him & manipulating him & he doesn’t even see it. I’m starting to think that all that last year, maybe, in part, maybe she was dripping poison in his ear, causing arguments between us on purpose to isolate him. But I don’t know what I’m supposed to do, if I say anything I know he’ll just kick off again, & it doesn’t change the fact that he was being an absolute arse before he even met her.