Does divorce take effect if the wife opens the door for her son, knowing that the husband made divorce conditional on opening the door by saying: "If you open the door for him, then you are divorced"?

The majority of scholars hold that a conditional divorce occurs upon the fulfillment of the condition. So, if a husband conditions his wife's divorce on merely opening the door for their son, the divorce occurs as soon as the door is opened. He can take her back before her iddah (waiting period) ends, provided this divorce does not complete the three divorces. As for Sheikh Al-Islam Ibn Taymiyyah and those who agreed with him, they believe that an expiation for a broken oath (kaffarat yamin) is required if the husband did not intend divorce. However, if the husband intended to condition the divorce on opening the door specifically for the purpose of an overnight stay, there is no breaking of the oath if the wife opens the door to her son merely to inform him that he is not allowed to stay overnight, as the oath is based on the intention of the swearer.