Do you have high speed internet? Mine is generally game to work on projects on the weekends, but his worst work deadlines always seem to happen on the last month of the summer. Meaning, the last few weekends before the winter rains set in and make things like painting the deck and using power tools outside impossible. All you will need to do is give him coffee in the morning, feed him 3 or 4 x a day (he has a fast metabolism) and make sure that he can hook up his computers and use the phone at all hours.
I don't mind finishing the last 25% of the project that he will leave, it's way better than the full 100%. There are goat sheds to put up, fencing to do, re-roofing the well pump-house, cleaning gutters, de-mossing the roof, maybe thinning some trees out here and there, and finishing the last 25% of the projects I start.
Oh, wait, I just thought of a problem....... He isn't one of those morning people, is he?