Losing mum

Hello… I dont know where to start with this… I lost my mum in August last year. She was a strong, fit and independent woman and we expected her to live until she was 100. She had a fall in February and gradually deteriorated. I am absolutely heartbroken and have no idea how to move forward. I live alone, divorced a few years ago. I looked after mum.
The added problem is that I have an older brother, 12 yrs older, who hates me and does everything he can to bully me and make everything nasty.
We are having to do probate for mum and it’s absolute hell.
I can’t grieve for mum because of all the anger and resentment from him and his wife.
I just dont know what to do anymore without my mum.