On May 1, Brown & Son enter into a written contract with Gary Green to paint his cottage over the July 1 Canada Day long weekend for $1000. On May 2, Brown & Son obtain a contract with the Langley School Board to paint the Sussex Middle School by July 15 for $5000. In June, Brown's son becomes ill. Without the help of his son, Brown feels that he will not be able to complete both the Sussex Middle School contract and the Green contract on time. Brown calls Green to tell him that the contract is off. Green agrees. The next morning, Brown's son makes a remarkable recovery from his illness, and he is back at work by that afternoon. Brown realizes that he can now finish both contracts on time. He calls Green to affirm that he will be able to paint his house after all. Green tells Brown that his services are no longer required. Brown reminds Green of the written agreement, and threatens to sue him. What claim, if any, does Brown have against Green? explain, issue, law, and remede this case.