Then treat it.
I am more than familiar with people like him. I have had relationships with people who made endless excuses, and refused to manage their conditions, and then of course, told me it was my fault. As if I was supposed to magically cure them of all their mental and physical issues... that they actively embraced and enhanced by poor habits and recreational drug use.
When it comes to mental and physical health, yes you do have to pull yourself up. Nobody can do it for you. Nobody can fix my health problems for me. It's my responsibility to manage them. Or I suppose I could just give up, and be a twat about it and incessantly whine to whomever will listen to my self-imposed misery. And go around taking random internet comments as personal attacks on myself... lol