It's Randall, Jack and Lureen's ranch neighbor. Apparently Jack was at least thinking about bringing Randall to Lighting Flat, his parent's ranch. He must have been seriously thinking about quitting Ennis, or he was at a very low point in his life, it's one in the same. Randall was the alternative to Ennis's non-committal. He was everything Ennis was'nt, sucessesful , and educated with a degree in animals and ranching. . , and the nerve to come on to Jack at the charity dance. . Jack apparently mentioned Ennis and Randall to his parents as friends who were gonna help Jack fix up the ranch and help run it. niether one ever made it.
Mr. Twist was expressing his jeaulous disappointment in Jack and his disapproval of his lifesyle. His mentioned of Randall was designed to hurt and humiliate Ennis at a time when the real nature of their relationship is understood. and Ennis realizes it. The old man has Some nerve for someone who shut his own son out of his life.
In my opinion, we can speculate about this relationship between Randall and Jack. Personally, I think they were occaissional lovers, but beyond that, we the veiwers are not privy to the depth of feelings here. There's a whole thread on him with various opinions and perspectives about him and how he fits in Jack's life.