Any chance she could convince him to go to the hospital for an evaluation? (Probably not, if he's manic, but it's worth a shot.) Not sure where you live, but in most places there's some kind of a mental health act that allows a hospital to admit someone voluntarily if they meet certain criteria (danger to self or others, suffering from a mental disorder, unlikely or unwilling to stay in the facility involuntarily.)
If he's doing anything really dangerous you could get the police involved, they can usually take a person to the hospital for a psychiatric evaluation-- but again, he would have to be exhibiting dangerous behaviour (to himself or others.)