If he is paying rent he has the right to have anyone he wants over as long as there is no criminal activity.
She cannot prevent you from helping your son move unless you are committing a crime , Simply helping someone move is not a crime. John W. Drury
So there is no misunderstanding, this answer does not create an attorney/client relationship and you cannot presume that I am your lawyer or that my advice can be relied upon in any way other than for information only. You will not become my client unless and until you retain me.