I certainly would encourage him to ride, but I wouldn't invest that much into it until you're sure he will. A friend of mine has scored some real nice kids' raod bikes on Craigslist for dirt cheap... I'd look that route before I sacrificed my own bike. Unless..... You're planning to use this as an excuse to buy yourself a new bike. Then, by all means!
Mark
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Bicycling is my drug of choice. Followed closely by beer.