Unfortunately, you cannot buy options, only the underlying stock after the option is exercised. It's likely the strike price will be in the thousands for this grant. Also, the company will likely have the right of first refusal on a sale, which means that if $100 is less than what the stock is worth, the company will simply repurchase its own shares.

This makes your plan quite a bit complicated and likely impossible to pull off.

Obviously, this was merely a rhetorical point.

In reality, various contracts could be put in place such that I provide $100 now in exchange for the rights to any eventual profit from his options.