When Bill died, he left all of his property in a trust to take care of his wife, Dorris, for the rest of her life. On her death, the money would go to their son, Rob. The Bank of Tulsa was the trustee of this trust. Fifty years later, Rob needed money, so he began writing checks out of Dorris's checking account. She knew about the checks but could never say no to him. At the rate at which Rob was spending her money, the trust funds would all be gone within a couple of years. What was the bank's responsibility? Was it obligated to let Dorris have as much money as she wanted?