My son believes he has schizoid personality disorder

He’s a diagnosed adhd but he is very undemonstrative, he has no friends yet can be charming when he decides to but its almost like a act, he loves me I know this yet it would never occur to him to say to me or show any affection I’m not upset I know how he feels he shows me when my bipolars acting up and he gets my meds. He isn’t particularly interested in socializing and some have said he appears psychopathic but I do not believe that to be true as I’ve never known a psychopath care if I chuck out the perfectly acceptable sofa or donate it but he appears unemotional and like he is playing a game when I’m fact he just puts on a act dependent on the situation but he does care inside. If you ask him how you look he will simply reply shrug and say ok, he can have friends anytime he chooses yet he chooses not too, he only ever does things which interest him.

If someone give themselves an identity, it means something, so you'd have to ask what it means to him, it's kind of an opportunity for communication. What does it says about how he wants to be seen, and is it what he truly wants for the future? that type of thing.