Is he grieving?

My 83 year old dad has lost 2 brothers over the last 5 years. He seems to have ground to a standstill- won’t even make a cup of tea. He’s obssessed with being ill even though he gets repeated clean bills of health and his attitude to my poor mum is awful. I don’t think it’s dementia but I’m suspecting that maybe the deaths have affected him and maybe the reason why he doesn’t believe or listen to his doctor (who is starting to run out of patience with him). When I try to talk to him I’m met with the most ridiculous levels of denial. I don’t know what to do to help them .

It sounds as if the loss of his two brothers has reminded your dad about his own mortality, and as he wont talk about it he is worrying more and more and taking it out on the person he is closest too and whom it will affect most, your poor mum.
How to tackle it I’m not sure. Perhaps try to do it through practical things first to get him talking- has he made a will, has he and you mum discussed what either of them will do if the other gets really ill or unable to cope.
Perhaps another way, and hopefully it wont make him feel guilty and clam up, but ask him if he realises that your mum is worried that he is/ or maybe worried.
I know it is going to be hard because I was in denial when Helen, my wife, was diagnosed with cancer but anything is worth a try.
Best of luck, take care.