Good grief, what a terrible situation.
First of all, contacting the attorney is a very good option. A trust is inherently a private document. Nobody has a right to a copy of it unless the trust document so permits, or the grantor (the party who created the trust) so consents to. She can even tell the attorney to ONLY provide it to her and only when she is alone, just in case she is later brow-beat into providing him with access.
Second of all, if he actually threatened her, the quickest way to get him out is via a restraining order. California law permits parties that live together to qualify as "roommates" which are covered under domestic violence
and protection from abuse laws. She should go to the site below, print out the forms, follow the instructions, and file it. He will be forced to leave the home, or he can be arrested, AND while the order is in place, he MUST give his firearms to the police (since a person under a restraining order cannot legally possess firearms). She will get a temporary order and once a hearing is set, she can go there and make it permanent. Here is the link:http://www.courtinfo.ca.gov/selfhelp/protection/dv/restraining.htm
Third, while all this is taking place, just in case the order fails, she can also evict him. Since he is an occupant, she will have to serve him with a formal unlawful detainer
letter which would give him 30 days to leave. If he fails to leave, she would be able to take a copy of this letter to the courts, file a complaint, have the court issue a summons, and pursue an eviction order. If he still fails to leave, the sheriffs will be able to compel him off the premises. Just make sure that she serves him the letter via certified mail, a third party, or by affixing it on his door.