Remember that Monsanto owns the cabin in the woods and helps Jack out by setting him up for three weeks of solitude at the novel's start. He's one of the few characters who recognizes what Jack needs, and can provide it for him in a way that Jack will accept. (Others try to help Jack, men like Cody who tell him to stop drinking, but few are effective.)
All you have to read here is Chapter Thirty, in which Ben comes to Billie's apartment, picks up Jack, takes him out for a walk, and watches over him as he sleeps for the first time in who-knows-how-long. Jack repeatedly refers to him as "old Ben" though Ben is actually his same age. Jack sees him as a protective, mentor figure. Though Ben doesn't instruct him with words, he does take care of Jack in a non-verbal way.
George is yet another non-verbal guide for Jack. Duluoz sees Baso as a spiritual guru, "the little Japanese Zen master," he calls him. When he describes the first night he met George, what he focuses on in George's spiritual prowess, his unique understanding of the Buddha. Words aren't what's needed for this kind of instruction.