I’ll add my two cents here too if it helps in any way.
Obviously losing a parent is awful and is something that will happen to us all one day. But he’s a parent himself and life goes on. He needs to either process his grief (alone or with help) or put up and shut up. You shouldn’t be playing a supporting role in your own life, you are a human being with needs of your own.
Also, easier said than done, but please don’t cling to the memories of the person he was hoping that he’ll change and it will all go back to how it was in the beginning. You’ll dream your life away, trust me I’ve been there. I spent months miserable, walking on eggshells, doing the most for little return and agonising over how I could fix it / what I did wrong and it only got worse.
Reading back this sounds quite matter of fact but I wish someone had said it to me and saved me some anguish, I hope it helps