What is the ruling of Islamic law regarding a wife who refuses to reside in her in-laws' home to care for them, while her husband claims that this is an act of disobedience on her part towards him, and he threatens to withhold her financial support, and is she considered disobedient (nashiz) in this case?

The preponderant opinion is that if the wife stipulates a condition that does not contradict the essence of the contract, it must be fulfilled. There is no blame upon the wife if she does not reside in the house during the husband's absence, and his family has no right to be angry with her for that. It is her right to reside in an independent dwelling. She is not obligated by شرع (Islamic law) to obey him in visiting his family, although it would be better if she did. The wife is not considered disobedient (nashiz) based on what has been mentioned, so the husband does not have the right to withhold her maintenance. Understanding and wisdom between the spouses are advised.