I'm sorry for your relative(s); my family also has been helped by meds. But I know the side effects can be extremely unpleasant.
I've been saying, that I don't know all the answers for this specific issue. I would think violent actions that bring LE to one's home (like the FL shooter) should be considered. I think issuing threats should count. I think telling a therapist voices are telling you to kill people would qualify. So might a restraining order. The FL case obviously demonstrates multiple failures by LE, school, and maybe medical professionals (?). We need to hold them accountable to do better, and we need to as a country get serious about this subject.
Bad behavior has been classified as an illness. That way the person is not held accountable. He is instead a "victim" of a condition, which is deemed beyond his control.
I am sort of old school. Once upon a time in the West, a townsman kicked the holy crap out of somebody that exhibited bad behavior. He didn't wait around for the next trip by the circuit shrink to town.
More often than not, the bad behavior guy, either shaped up or left town.
If he leaves town, then comes back with more bad behavior, maybe his days (or his days of freedom) need to end.