What kind of an account can be opened to ensure the minor's boarding school money is only used for?

What kind of an account can be opened to ensure that the minor's boarding school money is only used for boarding school? Both the minor and the parents desperately want the minor to go to boarding school. The school costs $25,000 a year. What kind of an account can be opened to ensure that the minor's boarding school money is only used for boarding school and the leftover money goes to the father at the end when the minor graduates?|||Prepay the boarding school.