Well like I suggested, show up with your mom the next minute Family court is open and have her ask the judge for a restraining order. They usually grant them and after the dude gets served he'll be on auto-arrest if he comes within 500 feet of her, which would hopefully allow her defacto possession of the house at least until he gets his day in family court. Family court is like small claims, you just show up and lay it all on the judge, who sees stuff like this all the time. Lawyers aren't required. Make sure she tells the judge that to feel safe from him SHE needs to live in that house and he needs to go somewhere else until this is resolved. If you're worried about him coming back, stay in the house with her, armed if necessary. Possession is 9/10 of ownership, right? Again that should buy you time.
Then go to the town or county or whatever and talk about the land issue. The town handles deeds, right? So they should have the power to block the change to the title, if one's even been made.
Then go to the bank and be like "yo whattUP?!" No seriously, kill 'em with kindness, but if they don't cooperate, threaten them with legal action.
Some well written letters might help.
If it's a lot of assets, the land and house, spending 3.5k would suck, but look at it as an investment. And most lawyers offer payment plans. And if you win, you can sue him for the lawyer fees, if he can afford to pay them...