What is the ruling regarding someone who swore an oath upon his son by triple divorce, and forbade him his wife's livelihood if the son were to leave the house, and the son then left?

The majority of scholars hold that swearing an oath of divorce effects a divorce upon breach, and that uttering "thrice divorced" effects three divorces. However, some scholars, like Sheikh al-Islam Ibn Taymiyyah, are of the view that swearing an oath of divorce, when the intention is not to make divorce conditional but rather to threaten or emphasize, takes the ruling of an oath by Allah, obligating the one who swore it to offer an expiation for an oath (kaffarat yamin), and no divorce occurs. They also hold that uttering "thrice divorced" effects one divorce. Accordingly, the fatwa given is that the son's leaving the house effects three divorces, and the husband cannot take his wife back unless she marries another man and is then divorced by him or he dies and her waiting period (iddah) expires. It is advised to avoid swearing by divorce or by declaring something unlawful, as it is not legislated.