R.M.
We are having issues with our 4 yr old friend as well. (our neighbor) i never allow our kids in others homes but the other kids are more than welcome in our house. 1. For supervision 2. For discipline.
I tell my kiddo that this is his house nad everyone here needs to follow all the rules. I still have a baby monuitor in his room and if they sneak in there i can hear what is going on. They can only play and watch tv in the community areas where they can be watched.
If rules are broken then there are consequences. Our neighbor is a little rough around the edges and does a lot of inappropriate things. We talk to him about it and treat him the way we treat our kids and he tries to tell us that we cant and he will tell his mom but to me that is ok and i want him to tell his mom . I am not hidiong anything.
I like the advice to ask questions and let them solve the problem
good luck and god bless. Stay on top of it!!