Yes, let him go.
If more Naes than Yaes then it's Portree on the Isle of Skye with us,
wait till you are a parent
Just make sure he's got his health insurance and forms all up to date. Just in case. I'm sure he'll be fine. But with all these stories about kids overdosing on dodgy E pills, stupid levels of alcohol consumption, contracting STDs or getting some fat bird from Grimsby preggers, getting glassed in bar brawls, knived, lost in foreign cities and set upon by north african gangs, it's always best to be on the safe side.
Let him go if he's mature enough to pay for it.
Went on my first lads week away back in the 80s to Benidorm when 17 years and 11 months and I was the oldest of the group. Got very pissed, got laid by a Dutch bird called Yolanda who liked my Cure t-shirt, ate crap, got sunburnt, took pictures of a comatose mate with his skid marked pants over his head and had to beg for the train fare back from Gatwick because I left my return ticket in the hotel in Spain. Great times.
He's paying for it,
He works in a chippie on friday and saturday night, and needs to stump up £50 deposit immediately, which he has, and the rest (£300) in June.