I don't think its really possible... He's not a Levrone. And even if he megadoses everything, just the training will be hard because of the post-op recovery. If he does compete, he'll be outsized by pretty much everyone.
It doesn't matter. Just competing in the Mr. Olympia is good enough. His name stays in the limelight, which equals guest posings and supplement deals. It's really all about what happens AFTER the Mr. Olympia (contracts, deals, etc.). Even if he places crappy, he is a household name. He will hold a few seminars about his "journey." This will include his injury, his recovery, and his triumph (competing at the Mr. Olympia). He will share the secrets to life and weightlifting with a room full of gym goers. Hold a few seminars, charge $500 a head, and he's good to go.