Right now it seems that he frequently changes the way he treats you. He changes daily if not hourly.

How satisfied are you with the way things are now?

If you are not satisfied, then you could establish some boundaries with him. You could for example say that since you are not in a relationship you are no longer going to see him. That will help you get over him.

With regard to his mental health, does he see a therapist? If not, you could encourage him to see one.