Pheeble Will

 is a quest in Fallout: New Vegas.

Quick walkthrough
Bighorner rancher Walter Phebus and his wife, Ethel Phebus have traveled to New Vegas on the trail of big-name rancher/robber baron Heck Gunderson. Walter seems bent on revenge after having some of his land taken by Heck in a shady deal.

Detailed walkthrough
Initiate conversation with Walter Phebus and find that he is in New Vegas and has trailed Heck Gunderson to the Ultra-Luxe casino. Walter tell you his troubles, and requests that you to find out why Heck is visiting the casino. You may pass a Barter check of 70 to recieve 400 caps for accepting this quest. Ethel will attempt to get you to persuade her husband to let the matter go. (To accomplish Ethel's purpose, you need a perception of 7 and then must pass a Speech check of 75.)(This will end the quest with an EXP reward of 375.)

After finding Heck in the casino with his bodyguard, you find that he is attempting to make a food supply deal with the White Glove Society, and that his son, Ted Gunderson is missing. This will initiate the quest Beyond the Beef. Upon informing Walter of Heck's troubles, Walter makes you an offer to take out both Gundersons. The reward can be increased to 500 caps for Ted if you pass a Barter check of 80 and 1000 caps for Heck with a Barter check of 90, or you may offer to just "take care" of them. One way to get Heck to a secluded area is to steal something from him and run to the penthouse door. He should follow you. When he get's there go in the penthouse, and run around the corner. When he gets there, let him get away from the door so he can't escape.

Completing Beyond the Beef by siding with Mortimer will result in completing this quest around the same time.

Another option is to run in refuse to hand over weapons and kill absolutly everyone

Bugs
If you bring Ted Gunderson to Heck Gunderson (while completing the quest Beyond the Beef) and talk to Heck Gunderson, then this quest will be failed, Walter and Ethel will disappear. Even if you kill Heck immediately.