What is the ruling on a mother imposing a monthly sum on her children and their wives, and alternating her stay in their homes to instigate problems, even though she is not in need of it?

The rights of parents are great, and the mother is given precedence in dutifulness. Providing for a poor mother is obligatory by consensus. However, if she is not in need, providing for her is not obligatory, nor is it obligatory to pay her a specific amount she imposes on you, especially if it harms you or causes you to fall short in another obligatory expense. It is best to give her what pleases her according to your ability. Do not leave her to live alone due to her old age and psychological illness. Be patient with her harm, observing her rights, and remember her favor upon you, for "Allah's pleasure is in the pleasure of the parent, and Allah's displeasure is in the displeasure of the parent."