First, Carfax only reports information that is sent to it by dealers, insurance companies and associated repair facilities. It does not search data bases for things like thefts or unrecorded transfers. That it doesn't show that the bike was stolen doesn't necessarily mean it wasn't.
The fact that it was found "abandoned" in the woods makes me, at least, suspicious of it's history. If indeed it was stolen, and the theft was reported to the police, you or your son could very possibly have an extremely uncomfortable experience when you attempt to register it. I would strongly suggest taking the VIN to the local police and having them run a check on it. If it comes back clean, you can ask them how to get title to the bike.
Because of the nature of how you found it, I suspect that if you can get a title, it will be a salvage title which makes the bike not worth very much, and possibly difficult to register for highway use. Still, if you are willing to do what needs to be done to register it, it is an ideal candidate for a cafe build.
Last, Ontario is a pretty big chunk of real estate, and I suspect that local laws might vary a bit from place to place, so it might help us understand what you are up against if you maybe narrow down your location a little bit. It can also help us make recommendations for sources of parts or service.
