Is rejecting many difficult demands of one's mother—such as her demanding the expulsion of one's brother from the house, or her demanding to sleep beside her instead of one's wife, or her insistence on sleeping with the light on when the son is unable to do so—considered an act of disobedience (ʿUqūq)?

Disobedience to the mother is not considered "uquq" (disrespectful disobedience) if there is no significant benefit for her in it, especially if it causes you hardship or harm. Care should be taken to apologize gently and try to convince her of your interest. It is obligatory to obey parents in matters that do not involve disobedience to Allah, unless it causes harm or hardship to the child. Obedience to them is not obligatory if the command or prohibition results from foolishness or lack of reason, such as a father ordering his son to divorce his wife. Although disrespecting parents is a major sin, it is difficult to define a precise standard for obligatory obedience and forbidden disobedience. According to the consensus of scholars, it is not obligatory to obey them in everything they command or forbid.