What is the expiation for taking a forbidden bank loan after the father forced his daughter to take it to pay off his debts, knowing that the daughter gives charity monthly, following His saying, the Almighty: "Take, [O, Muhammad], from their wealth a charity by which you purify them and cause them increase"?

Usury is one of the grave sins that are forbidden. The father's command or threat does not make dealing in it permissible, because there is no obedience to a creature in disobedience to the Creator. Whoever has fallen into this must repent, seek forgiveness, and feel remorse. He should pay back only the principal amount to the bank if he is able; otherwise, Allah does not burden a soul beyond its capacity.