Is it permissible for a mother to visit her married daughter without the husband's knowledge, given that the husband forbids the mother from entering the house due to disputes, but does not prevent his wife from visiting her mother, yet the daughter cannot visit her mother due to health conditions?

A husband does not have the right to prevent his wife's parents from visiting her, unless they are corrupting her against him or he fears harm from their visit.

Some scholars have gone so far as to say that the wife's parents should not be completely prevented from visiting, even if they are accused of corrupting her. Rather, they should only be prevented from the extent that causes corruption.

Therefore, if the mother is not corrupting the wife against her husband, he has no right to prevent her from visiting, and there is no sin upon the wife if she permits her mother to visit without his knowledge.