Legally Binding Contracts With Minors

[Michael Otis]

Not real estate related but just need a quick question answered. My friend, who is 21, sold a car to his sister's boyfriend, who is 17. He was trying to be nice and cut him a deal on the car but after it was sold, the minor damaged the vehicle and now his parents are threatening to sue on the grounds that a minor cannot enter into a contract but they helped him procure a loan for the said purchase. Does the fact they helped him get a loan to purchase the car make the purchase legally binding?