Is the questioner considered a disobedient son to his mother for her anger after he asked her why she took his maid to his brother's house despite his prior refusal, and is it permissible for him to ask his parents about the reason for their actions concerning something that belongs to him without his knowledge?

A son's question to his mother about her disposition of some of his money is not an act of disobedience (عقوق), and there is no blame upon him for it. This is because parents do not have the right to dispose of their child's money unless they have a need for it, the child is not harmed, and the purpose is not to give it to another child. It is recommended for the son to be gentle with his mother, treat her with kindness, and be good to her.