Old tenant keeps his stuff here and comes over often

[Shiloh Bryan]

Originally, a son and his father were on the lease. They are only family friends to us. Me and my fiancé moved into this household in January 2021 to take care of fiancé's grandmother. The son's father decided to go live with other family due to declining health. Before he left, he said he was completely fine with this transition since the lease needed to be renewed for the year anyways. That included his son leaving as well.

We now have the lease papers with only my, my fiancé, and his grandmother's name on it. The son is no longer a tenant and he is becoming a nuisance. At first, he was taking a few of his things at a time. Now, he's stopped altogether and keeps coming over to use his bedroom when his family kicks him out of their house.

We absolutely do not want him over here. He does not pay any rent or utilities. He is simply using this to his advantage so he has a place. However, he has stolen my fiancé's grandmother's valuables and money in the past, and he seems upset we are here to stop him from doing so. More recently, he has sabotaged (stole the catalytic converter for extra money) the vehicle my fiancé bought 3 years ago. This is all because he wanted our vehicle and got upset when we returned before he could take it from grandmother.

What steps should we take to get him to completely move out? None of us feel comfortable having him in our household. He told us he would move his stuff out eventually, but his old room remains full of his stuff. We are in need of this room so grandmother can have her own space.