Hi dolphinlover,
It sounds as if you're doing an amazing job trying to support your Dad.
I have lived with depression for most of my adult life and severe depression the last two years.
The best things people have done for me is to treat me like a normal person and continue to involve me I things, while some have been able to listen and support me too. I don't like people to make a fuss if I cry or struggle with intense emotions while they are around, but an acknowledgment that I'm struggling and helping me to calm down if needed is something a few people can do. Sometimes I need people to make decisions for me, like when a friend took me for lunch on my birthday, I was unable to choose the restaurant (out of 2) and she had to decide for me, or what I wanted on the menu so I chose the same as her. The fact she wanted to spend time with me when I was such poor company still encourages me now when I remember it.
At other times when I can make decisions I appreciate the dignity of being allowed to. Sometimes my friends and family have to be something of a mind reader and don't always get it right, but that they don't give up on me remind me how important I am to them has helped me to stay safe.

The most important advice I can give you though is to remind you that although your Dad is ill, he is still responsible for his actions and YOU ARE NOT.

I want to encourage you to continue to be yourself, the caring person that you are, a human being who cannot get everything 'right' whatever that is, but loves him enough to try.

Sending all the warmth and encouragement I can, and appreciation for the support you are offering him. ❤️