Is it permissible to refuse the mother’s request to own all of her working son’s money, given the son’s knowledge of her financial ability, and is the maintenance of sisters obligatory upon the son if the father is capable of providing it?

The mother's right is immense, and showing her kindness is among the best deeds. She is entitled to take from her son's wealth only what she needs. It is preferable to be gentle with the mother and to appease her with kind words and good deeds so as not to displease her. The financial support of sisters is obligatory upon their father as long as he is able to provide for them, and it is not binding on the questioner. However, if the questioner is able to provide for them and give his mother what does not harm him, that is better and carries a greater reward.