Sounds like you're stuck between a rock and a hard place. Sorry to hear that :/

I don't know if this is a great idea, but... if he's having psychosis and you're not sure he's telling you the truth about his pot usage, can you bring him somewhere to have his blood/urine tested for pot? This could be done at an dr's office or urgent care center instead of a hospital. If there are no traces of pot, then you know it's probably beginnings of BP or SZA?