So the latest shooting (I guess I have to specify that I'm talking about the one in El Cajon, CA, since it will likely be superceded by another shooting in a week or two, and then no one will know which incident this post is referring to) once again highlights how dangerous it is to call 911 for a friend or relative who is having a mental-health crisis.
As I understand the basics of the situation, the man's sister called 911 for help, and the 911 dispatcher sent police, who killed him. I don't think we have a lot of details yet; for instance, I don't know the nature of the man's "episode", but he's been described as running out into traffic.
I don't know what alternative the woman had, though. I suppose if other able-bodied friends and relatives were available, they could maybe talk to or physically restrain the man. At the same time, a person could lie to the 911 dispatcher about the nature of the emergency, so that only an ambulance is dispatched, but I can imagine paramedics arriving to see an adult man in the grip of autism, psychosis, schizophrenia, or dementia and calling the police for help. Restraining a person who's truly out of control can be difficult if there are 4 or 5 of you.
Additionally, the police are defending their actions not by claiming that he had a weapon, but by claiming that the man had "assumed a 'shooting stance'." It remains to be seen how far such a claim gets them.