I'm 40 this year but came at this from the other side , got kicked out at 17 as in mums words 'me and berni are getting married and I don't think you 2 will get on living together'.
My dad was unable to help as he was re-married with 2 young children in a 2 bed house so my dad's mate who worked in the council at housing pulled a few strings and got me a flat , all was well till I turned 18 and got a credit card! I think you can guess the rest.
18 months later I'm up to my eyeballs in debt and about to be kicked out of the council flat. Mum bailed me out to the tune of £1500 not a lot by todays standards but a small fortune to me then. I moved back home under the proviso that I would pay 25% of everything except the mortgage and do a fair share of household chores i.e. I was paying my way and not being kept apart from the roof over my head.
i got a part time pub job on top of my normal job and paid mum back everything in 6 months then 4 months after that got my firts mortgage with my girlfriend(who's now my wife)
As long as you're son understands it's not a holiday camp you should be fine.