A broker employed to sell real estate has discharged his duty when he produces a purchaser able and willing to buy upon the terms and at the price fixed by the seller, regardless of whether the sale is ever actually consummated or not, provided the failure is not due to some fault of the broker, and even although the sale is afterwards enjoined. Gibson v. Gray, 17 Tex. C. Ap. 646, 43 S. W. 922.