I feel that they are not sharing a good relationship and also have a problem in understanding each other. U need to read the article “Sanatan and Western Culture”. Your friend need to discuss the issue with her MIL in detail and tell her clearly that relationship always works when it is on mutual basis. Unless one reciprocates in same manner, the other can’t carry it too far. If she does not understand the needs of her children/ grand children now, then she should not expect anything from other side too. There is no logic in having arguments with spouse.