It sounds like the family did the right thing. They did NOT call the police, they contacted LA’s mental health team, who sent a mobile response unit.
The issue with mobile crisis teams (which most cities have by now) is that they won’t do anything if there’s a weapon besides call the police. That’s where things went south.
There needs to be more collaboration between mental health response teams and police to prevent this sort of thing. Also, wtf is the point of carrying a taser if you pull out your gun on a dude who is barely moving and holding a knife? Probably didn’t even need to be tased.