There's two ways to answer the question.

If your client really want's to learn how to fly. Enroll in AOPA's legal program, because you'll need it. Have your client take and pass the written exam. Have him obtain a thrid class medical. It would be tough for the FAA to say that he's not serious if he does both. Have him talk to the owner of the flight school about insurance. I have found that all insurance issues can be resolved by money. Have your client pay for the required coverage. Think about doing some of the training in the C-182 (talk about insurance on this one too) and having him do his solo flights in the single first. Sell him on the idea of getting both the SEL and MEL tickets at the same time.

If your client really wants to just fly to and from meetings, then have him do it above board either in his own plane or under a FAR 135 charter basis. Your ticket is worth far more to you than one "whale" client. You will be turned into the FAA. There are too many people out there that would call it in.