can I get help identifying all the legal concepts/elements to make sure i bring up all the points to these arguments?

Part 1: Stephen Muka owned U.S. Robotics. He hired his brother Chris to work in the company. His letter promised Chris $1 million worth of Robotics stock at the end of one year, "provided you work reasonably hard & smart at things in the next year." (We should all have such brothers. ) Chris arrived at Robotics and worked the full year, but toward the end of the year Stephen died. His estate refused to give Chris the stock, claiming their agreement was a personal satisfaction contract and only Stephen could decide whether Chris had earned the reward. Comment. . Explain the arguments that Chris can make . Explain the arguments that the estate can make . Evaluate the arguments and give your opinion on who should win