Is the wife sinful if she refuses to visit her husband's family, or his sister, or his aunt, and is she obligated to obey him in that regard?

It is recommended to supplicate and entreat Allah to reform the husband and soften his heart. The wife is obliged to obey her husband in what is good and permissible, including visiting his family, unless this entails harm or something forbidden. The relationship between spouses should be based on mutual understanding and respect, not on command and obedience.