I don't think the laws that make it virtually impossible to commit some one involuntarily to a mental institution are peculiar to CA, and may be Federal rather than state.
OTOH, SF governance and climate (= weather) do attract bums. One particularly egregious bit of stupidity is so-called "needle exchanges". They were sold as addicts turning in one used needle to get one clean needle. The turning in part doesn't happen, so it's just a program that enables addicts' lifestyle of addiction. These programs are the reason thousands of used needles are found littering SF streets and parks every month.
She has no standing to get the guy committed or even in for an eval, especially before the attack.
All she can do is report the attack, provided she survives long enough.
I don't consider that to be a "meaningful response".
What I was referring to is the renown difficulty in parts of California in getting a concealed weapons permit and a firearm, to respond to any such attack when it occurs.