First, the solution to the problem is to sell the house.
Before buying a house, you must pay off the balance of the bank loan. If parents don't have the money, you can either borrow it from relatives and friends first, or consult with buyers. The buyer will pay enough to repay the balance of the bank as a down payment, and the bank will inherit it after the money is paid off. The heir is set as one of the father or mother. After the property right is changed, it will be sold to the buyer by the new property owner (that is, the heir) and the transfer formalities will be handled!
I don't know if you are satisfied or understand my answer. If you don't understand anything, please ask again and I'll answer it for you as soon as possible!