Is a husband entitled to force the children to stay overnight at their grandmother's house despite the mother's refusal? And does the mother have the right for her children to be with her? And what is the Sharia ruling on the husband's behavior who considers his wife disobedient (nashiz) for refusing this matter?

The responsibility of raising children is shared between both parents. The wife should help her husband be dutiful to his parents. There is no harm in one of the children sleeping over at his grandmother's, who lives in the same house. This arrangement, along with the mother remaining in a separate apartment and finding comfort in one of her children sleeping with her, is preferable to avoid problems between the wife and her mother-in-law. The wife should not be upset or make this a cause for dispute; rather, she should strive for a pure relationship with her husband and help him fulfill his duty of righteousness.