I'd rather say: buy a small refractor such as [url=http://www.bintel.com.au/Telescopes/Refractor/SkyWatcher-SW102/140/productview.aspx]this Skywatcher 10cm Startravel[/ur]. Ok, less aperture but far more convenient to handle and *really* maintenance free. No collimation hassle (for a 12 year old boy it can be a hassle). No such things as 'Daddy, can you bring the telescope outside' or 'Daddy, can you collimate the scope, I see fishes instead of stars'.
I have a friend (a well experienced astrophotographer) with a 13 year old son who has a simple
10cm tabletop Dobson and is very happy with it.