Unfortunately over the past few years my stepfather has become increasingly unstable and in his current condition can best be described as an angry and undisciplined child with all the powers of an adult and no respect for any authority above himself. Several months after suggesting a 302, my mother has finally started to cave realizing she needs mandatory help. I won't go into a full list of issues but there is genuine cause to be concerned for the welfare of others.
I understand the process of going to the local magistrate, requesting a petition, having law enforcement present if necessary, etc. My mother's question and fear is "What happens after the 3 days" or however long they evaluate you. She's concerned about two things. One is that he could somehow snake his way out of a psych evaluation by playing a perfect role and saying we're just conspiring against him for some reason, in which case there will be no point to a 302. The other is that after the evaluation or any time in a hospital he would be sent back home and this might be just enough to push him over the edge and think up some way to kill her as revenge.

So other than making access to guns illegal, what exactly does a 302 do to help protect the caretaker?