What is the ruling on a wife refusing to let her infant son visit her husband's family (the grandparents and paternal uncles) due to family problems, which has prevented them from seeing him since his birth, and does this lead to serious consequences?

If the marital relationship is ongoing, then custody is a shared right between the spouses. It is not permissible for the husband to take the child alone and visit his family without the wife's consent, especially if the child is young and there is a fear of harm from separation from his mother. The husband is advised to strive for reconciliation between his wife and his family, to encourage dialogue and understanding regarding the child's visit, and to be patient with any harm, while being keen to avert harm from her and to reduce the duration of the visit if necessary.