not paying rent tenant or guest?

[Andre Curry]

Im allowing my homeless brother and his wife to stay in a fixer upper I just acquired for free until it is fixed up. Since they aren't paying they're considered guest right? The place is in horrible condition currently but they dont care for obvious reasons. No lights, running water etc. I told them they could get the lights and water turned on if they wanted. Would that be a problem if its in their names? Also, this is my first rental property and I have no idea what im doing yet. Reading some books and watching videos on youtube to learn more. I just dont want to end up getting screwed by letting them stay there. Thanks for your time.