What are the rights of the wife’s family upon her husband and vice-versa in Islam, and what is the religious ruling regarding a husband who has not visited his wife’s family for more than three years despite having two children, and what should be done about him?

The mutual right between the husband and his wife's family is the right of Islam. It is recommended for both parties to maintain ties and show kindness to each other to strengthen affection. This is indicated by the general commands of the Sharia concerning communication and compassion among Muslims. The Messenger of Allah (peace be upon him) said: "Spread greetings, feed the hungry, and be brothers as Allah has commanded you." He also said: "You will not enter Paradise until you believe, and you will not believe until you love one another." And: "Do not hate one another, do not envy one another, do not turn away from one another, and be servants of Allah as brothers." He also said: "It is not permissible for a man to forsake his brother for more than three nights," and "Whoever believes in Allah and the Last Day should honor his guest." Therefore, the husband should not ignore his guest; rather, he should honor him. If the husband has a legitimate reason for avoidance, such as the wife's family openly committing فسق (immorality) or بدع (innovations), then he has the right to do so. However, he must consider what is most beneficial and leads to love and harmony among Muslims.