Please answer as soon as possible

Case 3 Jake had long coveted his elderly neighbor Elwood's property. It was larger than his lot and offered an unobstructed view of the Niagara escarpment. Elwood had often expressed to Jake that the property was getting harder and harder for him to manage on his own. One time, over coffee, Jake offered to purchase Elwood's property "whenever he was ready to sell." Elwood thought about it for a moment and asked, "How much?" Jake told Elwood that he would arrange for three appraisals and that they would throw out the high and the low appraisal and that he would pay Elwood an amount equal to the appraisal "in the middle". With that Elwood said "deal" and shook his neighbour's hand. Two weeks later, Jake arrived at Elwood's home, to talk about the timing of the three appraisals, only to be told by Elwood that he had changed his mind and was now going to leave the property to his two children. What recourse does Jake have to enforce their contract