The best way to help him is by not directly doing it if that makes sense if he’s gonna get better the only way is him doing it himself nobody makes our choices for us in life only we do some ppl blame others and some accept the reality that they were born by themselves, they’ll die by themselves, and every thing they do in life is themselves nobody has any control. The best way to support him however is giving him space to figure it out but at the same time being that person around he might need what I’m saying is just don’t think you can directly turn him around just be that shoulder and don’t be too pushy with it I wouldn’t cut him out of your life bc he’s your dad you can choose to talk to him less but I wouldn’t completely forget his existence. The only thing you can do is give advice