He is definitely showing symptoms of some form of mental illness. And luckily for you, there are now plenty of resources to tap into to get him the appropriate treatment he needs. FIRSTLY, I would approach his family and find out if there is a history of any mental illness in the family. Also ask them to assist you in getting help. If he becomes unstable, depressed to the extent you are worried, then as a family unit, approach his Dr and depending on who is his NOK (ne t of kin), that person can ask a Dr to schedule them under the Mental Health Act. This sounds severe, but if he's at this point, he needs to be assessed no treatment started before it becomes out of control. You will have the normal feelings of abandonment and guilt - get over this. This is about getting HIM help, not how you or his family feel. By getting them scheduled, they must, by law, be admitted to the nearest psychiatric facilities where he will have 24/7 access to mental health specialists, specifically trained in this area. You will find, they will assess and monitor him continuously until they (a team of specialists) discuss his case, and then he will be given an official diagnosis and treatment can start, and once stabilised and he will also be educated - as well as family on what to look for and where to seek treatment if his condition declines once home ( for eg:, if he feels good, thinks he doesn't need the medications and stops taking them etc - that kind of thing).
They may may link you or him up with community mental health services who will keep track of his condition once he returns home. So maintain the he appointments with both the mental health services and his designated psychiatrist.
He will resist any attempts to yget him help. He will flat out refuse to go, so expect this, along with him becoming very vindictive and name calling - everything he can do and say so you will feel guilty and "give in" a IGNORE THIS! Keep your self focused. He needs a diagnosis and care and needs it NOW!
If if his family start to back down and feel guilty, as he will attack verbally them as well, tell thim hem to resist giving in. . YOUR MAIN AIM IS TO GET HIM INTO A SECURE, SAFE FACILITY, GET A THOROUGH DIAGNOSIS BY PROFESSIONALS AND THE APPROPRIATE TREATMENT! ONCE STABILISED, HE WILL BECOME "NORMAL" AGAIN. THEN THE ENTIRE FAMILY AS A WHOLE, WITH HIM WILL RECEIVE COUNSELLING, EDUCATION ABOUT HIS DIAGNOSIS AND WHAT TO LOOK FOR IF HE DECLINES ONCE HOME AND WHAT TO DO IF THIS OCCURS. REMEMBER IF ANYTHING AT ALL, YOUR GETTING THE HELP FOR HIM, NOT YOU OR HIS FAMILY, SO TOUGHEN UP, AS HE WILL FIGHT YOU ALL THE WAY, BUT HIS DR CAN GET HIM SCHEDULED IF HE WONT GO VOLUNTARILY!
Good luck
Dialysis57