He shouldn't be asking you to fix him, you can't. He can by taking his meds and getting professional help.
If he broke his leg would he assume you were qualified to treat him? Of course not, he would go to the hospital.
What a bizarre thing to expect from you.
Your gonna grow up real fast once this baby is born, don't be surprised if he doesn't.
Few things will put a bigger gap between a couple than poor mental health and a baby.
How is he gonna respond when you don't have the time or energy to give him all these pep talks and attention.

There will be no more snuggling the day away either.
Focus on being a good mother. That includes taking care of yourself and your own mental health. Let him learn to figure out just what he wants.

Has he always been like this or has it gotten worse since the pregnancy?