How can one deal with a demanding mother-in-law whose demands affect family and marital life?

The wife is not obliged to give the husband’s mother anything from her possessions. The husband is not obliged to give his mother anything as long as she is self-sufficient, except as a voluntary act of kindness and benevolence, provided that it does not compromise his duty to spend on his wife and children.

The wife should be kind to her husband’s family and overlook their mistakes. She should gently and wisely advise her husband on balancing spending on his mother, when not necessary, with spending on his household. She should not let Satan fill her heart with malice and hatred; rather, she should pray for her well-being and occupy herself with beneficial matters.