Bill owns a rare vintage Ford Mustang automobile. Jack, one of Bill's closest friends and a physician, has persuaded Bill to sell the car to Jack at a price substantially less than market value. At the time Bill sold the car, he was resting in a nursing home recovering from a serious illness. If Bill desires to set aside the sale, what arguments might he make?

Bill's best argument is that true assent did not exist. Given the close relationship, and if Jack was Bill's physician instead of just a physician, Bill may have exercised undue influence. Bill will need to prove he was vulnerable and that Jack, as his friend and doctor, knowingly took advantage of his diminished state. Even if Jack was not Bill's physician, it is still possible to prove that undue influence, but it is a more difficult case. No problem of consideration exists because consideration is about an exchange, not the value of what is exchanged.