What's the rule violation? Not saying there isn't one, I'm just clueless.
813.02 A player must not use any device that directly assists in making a throw. Devices that reduce or control abrasion to the skin (such as gloves, tape, bandages, or gauze) and medical items (such as knee or ankle braces) are allowed. Placing an object as a directional aid is not allowed. An item such as a towel or a pad may be placed on the lie as long as it is not greater than one centimeter in thickness when compressed.
Did the umbrella directly assist him in making the throw? Pretty obviously not.
If the umbrella was touching the ground in front of the lie, it could have been a stance violation.