Is it permissible for my daughter to wear the Eid clothes that my husband swore she would not wear on Eid, given that he has forgotten his oath and now wishes for her to wear them due to his financial circumstances, and would divorce occur if she wore them?

A husband must not jeopardize his marital life by frequently swearing oaths of divorce, and the wife should not provoke him to do so. If the husband forgets what he intended when he swore an oath, the oath remains absolute, and he breaks it by anything that contradicts its apparent meaning, unless he had an intention that restricts it, or there was a reason that prompted his oath.

If the reason for the oath was solely to buy the dress for Eid, then your daughter may wear it after Eid without breaking the oath. However, if the reason for the oath was the purchase absolutely, then it is a conditional oath, and divorce occurs if the condition is met at any time, and the husband cannot undo it. The preferred course of action is to sell the dress and buy food or similar items with its price.