Agh. Well then, sorry to have caused offence to so many. I've been away from MN for a while - maybe it's got more polite in my absence! 
I spend too much of my time these days interviewing and interracting with children in their early twenties who have never worked. They make my teeth itch. This idea that studying is such tremendously hard work that they couldn't possibly... ANYWAY.
I think they learn far more useful skills in a job than at uni - and you can tell the ones with proper work experience a mile off (and no, I don't mean internships...). They're usually far better prospects.
Your son has clearly done very well to save up, but I would encourage him to continue working a bit while studying and develop those skills further too. And lord knows he could probably use the nest egg once he graduates. Not least so he can fuck off somewhere for a year, if that's what he wants, without worrying about having a debt to pay off.
I just think it might form a part of his decision making is all. What else he might want/need to do with those remaining four days and evenings, and where/how he might best do that.
For what it's worth, I did an art foundation, which kept me at home for an additional year (no funds available to live out since we lived too close to college, and since it was full time I'd have struggled to earn enough to pay rent and bills). I spent half the time sleeping on people's floors so as not to miss out, and the additional year at home nearly did for my relationship with my parents. It was all a bit of a nightmare. But then I've always been a PITA independent person – I really needed to be out on my own after A levels.
Much as I adore my two, they'll be out on their ear at 18 if I have any say in the matter (which since it's my house I suspect I will...).