Is it permissible to borrow from parents who work in usurious banks for the purpose of marriage, with the intention of repayment, and is marriage considered one of the necessities that permits this?

If all of the parents' money is from usury (riba), then it is not permissible to borrow from it or to engage in financial transactions with them. One should seek another way to get married, for "whoever fears Allah - He will make for him a way out and provide for him from where he does not expect." However, if some of their money is lawful and some is unlawful, then borrowing from it is disliked (makrooh) but not forbidden (haram). The most cautious approach is to distance oneself from anything that has a semblance of unlawfulness.