I'm going to go against what everyone else is saying here. I don't think you should take what he said personally. What goes on in your sex life doesn't just affect you. It also affects him. I think he's just pointing out things that can be improved. Although, he could have been more tactful in the w...
I think since you already told her how you feel, there's not much to do anymore. Unless, you're willing to risk your friendship with her. In that case, you can say that you still love her and you can't hang around her anymore unless she wants the same thing that you do.
My parents can also be toxic. That's why I limit my contact with them. It bothers them. But I just have to remind myself that my sanity is most important.
If it's a psychotic disorder that's causing all of this, then I'm not sure there's much you can do. Just try to pay attention for little signs to see if there's reason to bring him in for 24/7 observation for suicide watch.
I wouldn't mind going to a young psychologist because they've got the schooling. But a life coach would need to have life experience to be able to coach. At 20, you've still got a lot of life to experience yourself.
This sounds like a very unbalanced relationship with you taking up all of the responsibility and not getting back much affection in return. It's an easy path to resentment.