My parents ran an apartment building in Lakewood, OH for over 26 years, so I may be able to offer you some help.
Here's how it works, and it's up to you how you want to handle it.
She should serve a 3 day eviction notice for non-payment of rent. If the person does not leave within the 3 days, you can get a court order and have them legally removed and the place will be padlocked by a baliff. They're given a timeframe to vacate the premises. Then, they have to come to you to get their stuff out and you can be done with them. If they don't come to you and retrieve their stuff within the timeframe, they forfeit the property. Unfortunately, though, it can take a couple months to get a court date if it comes to that.
As for the lost rent, unless you have the money for attorney's fees and court costs, and are prepared for months of court visits, forget it. It's not worth the time and effort, and like your mother says, most landlords never get it back even WITH a court order.
Hope this helps........I am NOT an attorney though, so don't take this as sound legal advice. This is what I've seen done in my parent's apt complex.