Please advise re eviction. I need help with this!?

My mom is 87 and lives 50 miles away in her home. I have services caring for her 7 days per week and a grand son who stays there at night to "be there". All has worked well for the past 16 months until he let his friend and friend's girl friend move in this week. I had told him he could not have anyone else living in the house as she is on a tight budget. These free loaders moved in with all their furniture. The home belongs to my mom ( I am legal guardian ). They refuse to move out now and the police say I need to give them 30 days notice and file eviction papers with the court system. Are they all kidding? they will destroy the house, eat her food and use her utilities. They refuse to go. Grandson is not cooperating either. What can I do? My mom is very fragile and had dementia.