Unfortunately there is likely no real help available for BJ, just chemical or physical restraint. He's probably not dealing with a chemical imbalance that's fucking up his brain and might be mitigated, allowing him to lead a more normal life, by appropriate medication; he's most likely dealing with extensive physical damage to his brain that cannot be meaningfully treated in a way that allows him to live an unrestrained life without being a significant danger to everyone around him. BJ's lot in life is past the point of being capable of improvement. BJ isn't traditionally schizophrenic; he's severely, untreatably brain-damaged.
BJ's family better get him the help that they need to stay safe from him.