When I had depression 2 years ago, I was thankful that my family just treated me as if I was physically sick. They let me sleep on entire days and they’d buy me the foods that I wanted. When I was a child I loved it when my mother gave me sponge baths every time I had a fever. Maybe you can let him go back to that little child in him and just nurture and spoil him for a bit… I don’t know if this will help you but I wish you well.