It's so nice people have replied, I feel totally isolated when all his friends are going and their parents don't even hint at it being impossible.
I don't think it's ever impossible - it would be very unusual for someone's parents to tell them it was, I think.
The demographic of MN seems to mean that a lot of parents here help their children financially, to a varying degree, at uni - and whilst a lot probably don't, the norm here is certainly that you do, so those that don't probably don't post about it much.
I've experienced two unis (I went and then DP went and I lived with him), and in both cases, 75% of students didn't have any financial support from parents. Most were living off loans, savings and part-time work. We all did bulk-buying of huge amounts of food/house products to last as long as possible, and saved money wherever we could. The parents were supportive, don't get me wrong, but it tended to be a food shop delivered once in a while, or helping to move things, or paying for study guides.
My parents didn't support me at all - I got more loan and a grant because I am estranged from them. DP's parents just couldn't afford/didn't want to subsidise him at uni, and he got the minimum loan, it didn't even cover his accommodation. I worked and we were thrifty. It's do-able.
Your only issue will be if he is expecting handouts, but if you talk to him and let him know that you'll support him when you can (driving him up/food parcels now and again/letting him come home for cheap rent over the holidays to save money/whatever), then he can work the rest out.