Foster teen coming to live with us on weekends

I live with my older brother he’s currently my guardian and he’s thinking about doing this program where he’s gonna invite a teen who lives in a group home from foster care to stay with us during the weekends. There’s a whole process he has to go through and said it won’t happen most likely until next yet but I’m kinda nervous. I had a friend it the past who was in foster care and she was really cool but I just don’t know what to expect. I’m scared I’m gonna get tired cause I usually don’t like having people sleep over the house, or what if they’re mean to me, or what if they don’t like me, or what if they steal my stuff. What should I expect?