Go and collect, hve a mate or 2 along and let them stand a polite distance away with a couple of camera's, one video and one still.
His mates would only have to stand at the end of the property in full view of the door.
Your brother in law need only be polite and ask for payment.
Violence is unlikely, but don't let them get away with such intimidatory behavior.
If he is still unpleasant, don't argue, but do mark his card.
Revenge can be all the sweeter when its a long time coming, you don't need to egg his house....he has a car doesn't he?
Wait a few weeks and egg that instead, better still, wait till the warmer weather gets here before you do it, dried egg is horrible to get off.
And al the time you are quietly dissing him to all and sundry.
Or be really nasty, mash up a fish and stuff it into his air vents, the stiink of rotting fish will be there for weeks
My tongue is of course firmly in my cheek with all of the above (apart from the camera to record him) I would never dream of doing anything like this myself :
..........it isn't nasty enough
Ian