Inlaws complaining to DIL's Parents about her

My in laws rather my FIL has to complain to my parents and my sister too all the time. He gets an earful from everybody including me each time yet he continues doing it.At the same time,I have an outburst with my husband here too after those episodes.Its been 7 yrs and he continues inspite of all this.:rant:rant.
He comes up with something new to complain about each time.Initially it used to make me have fights with my husband and crying episodes. Now I just laugh at all the things he comes up with. It just tickles me now.