Maybe the police would be more helpful if you and your mom met with them during a time of NO drama. Make a plan w/them for the next crisis, they can explain the options to your mom, if she can get some sort of conditional restraining order, etc, etc.
I waited a long tiime to go to Al anon b/c of my anxiety. Since I began going, my anxiety has lessened and I have so much more peace in my life. best of luck to you and your mother.