This whole thing sounds to me like he's got some serious mental issues that need to be diagnosed and treated in a mental hospital setting, without the brother interfering to get him out. He wasn't in the hospital long enough for doctors to really observe and diagnose him properly, let alone treat him. Risperidone (Risperdal) can be used for both schizophrenia and bipolar mania, and this change in mood / personality he's recently gone through could certainly be caused by either one. The fact that he is refusing the medication seems to indicate that he doesn't want to change back to the wonderful, loving husband he once was.
Is there any way the family could meet (without the husband present, of course), and agree to get him back into the mental hospital for his own good so he doesn't harm himself or anyone else, and to let him stay there until the doctors can get him properly diagnosed and treated? The best thing for him would be to get the help he needs, without anyone interfering to get him out before he gets through this.
_________________
You can't tell which way the train went by looking at the tracks.