It might be possible to turn it around. I got off on the wrong foot with one of my new neighbors, after being tortured by both previous ones (one was a nurse on shift work, who expected me to magically guess when she was (actually!) sleeping. A lot of times I had NO PROBLEM figuring out she was in bed!). Anyway, new neighbor moved in during the summer, and promptly started going in and out the balcony door (slam slam slam) like a dam cat, yakking at the top of his lungs on his cell phone, and the sound just CARRIES here. I lost it and yelled at him before I even knew his name. But I later apologized, and thru various elevator encounters, he has gotten to see the REAL me, I think? and learn I am not really such a hag, and we are pretty friendly now, considering I am old enough to be his grandmama. So - maybe the brother-in-law is more afraid of you, than you are of him? They can't possibly have thought they were really going to get away with the drum playing. The parents are probably thanking YOU, they just made you the fall guy. Hmm, I'm starting to think I should get a job as a spin doctor!