I would definitely NOT use the press on the documents issue-- it will inflame someone who is already dangerous. To protect herself legally in the case of identity theft and/or liabilities, your mother should run a small-type legal notice in the classifieds ("Not responsible for debts" sort of ad) as well as a notice that doc's have been reported stolen to the police. Yes, I know, the cops are not helping to recover them, but I think they do have to at least take the report. The date of the reporting of it may later become an issue-- a potential loose end to be sure is covered. (Be sure to get a copy of the report or the report number and badge number of cop who takes the report, to help in getting docs replaced.)
I also would not take large, scary-looking men along on any potential run-ins. Large men in clergy garb are a safer, less-inflaming alternative. It is not, not, not a good idea to exacerbate feelings during thie "leaving" time, and it's not just your mom who may sufffer retaliation, unfortunately, but also anyone perceived as helping your mother to get away. If he perceives that she is gaining in power, in any way, that will give him all the excuse he needs to keep trying to excert control.
And screw the cat. Sorry, Sorch, but people come first. [insert several million ! marks] Report cat abuse to the local SPCA and let them handle that end of it after you and your mom have left the area. (Report the cat stolen or lost as well.)