yes , you are right this happens. money and lack of luxuries that money brings the worst out of people. since you have asked for a open opinion. Here is a perspective and my 2 cents. keep the husband out of siding anyone. this is not the fight which he should be involved. ask the girl to tell her mum to move with her bro for sometime. OR rent a single bhk for mum. you are a 3rd person, see the views are all soft and all analytical , just imagine, if instead of mum it was MIL. by this this time this thread would have become 6 pages about how she should be kept separate. this is same problem just different flavor, solution is same. if parents cannot adjust to the couple, they need to live little separate - not too far but separate enough to keep the peace.