I would first attend that person's actual training sessions to judge his quality of delivery in a live setting.

Once convinced, the next question is the revenue sharing ratio. If he is doing most of the work, including development of the training material, while he is using my training company name then I would consider something like 70:30, to him after paying for all the direct expenses.

Of course, if the course fails to sell enough seats and is cancelled, or not cancelled but does not breakeven then the costs incurred including those on promotion should be evenly split.

You are free to negotiate any other ratios.