Those people sound psychotic! If I were your DD I'd be thinking very hard on whether this is a family I want to be involved with long-term. Unfortunately, when we marry someone we are also marrying their family. My MIL is a royal PITA and has said and done some really exasperating things over the years that make me so envious of my friends with wonderful ILs. My MIL's obnoxiousness has not been a total deal-breaker (in large part because she has always lived out-of-state), but I have friends who have true "monster-in-laws" and it has caused irreparable damage to their marriages.