I would assume that the only way anyone can legally "kick out" someone is to have that person sell their portion of the house back to the other owner. You can't divorce someone you were never married to. This is one of the many reasons that "living" with someone scares me!

I do hope you guys can get it worked out, and that he will leave. I wonder if your mother offered him a sum of money to buy him out if it would work. I certainly wish it would! I think she needs an attorney, and fast!