im a peaceful man,
but fuck it he's extended family fucking up ur immediate family,
id say beat that motherfucker to within an inch of his life,
personally i wouldnt know when to stop,
then say to him if u ever find anything again, u will kill him.

p.s. dont actually kill him, but if u do have reason to suspect anything again, just report him when u think hes got stuff in his house, then book ur mother into treatment