What is the ruling on expiating an oath for a father who swore by triple divorce upon his son to prevent him from communicating with a girl, knowing that the son has already communicated with her?

Swearing an oath by divorce is considered a conditional divorce by the majority of scholars. It takes effect upon the occurrence of the condition sworn upon, even if the intention was merely to threaten. If one swears by triple divorce, it results in a triple divorce. This is the fatwa we adhere to, and accordingly, a major irrevocable divorce (al-baynunah al-kubra) would have occurred. Some jurists are of the opinion that if one intended only to threaten and not to divorce, then only an expiation for an oath (kaffarat yamin) is required. It is necessary to refer back to the father to ascertain his intention. One must be keen to honor the parent and avoid verbal disputes with him, and one must beware of the temptation of women and avoid swearing oaths by divorce.