He'll be fine, you'll spend the week worrying, though!
Eldest went to Malia last July with a group of a dozen. He had a wow of a time although he went for 10 days which he admitted was a bit too long.
He turned 18 out there and came back minus his hair and eyebrows
I've seen the photos on Facebook and a lot of drink was consumed!
They do need to be careful about money, though. Between the group they had about £700 stolen (one lad lost £300 from the safe - he'd hidden the key in the microwave). It sounds to me like someone in the hotel was doing it but of course you can't prove what cash you had.
Luckily my son didn't lose anything but we had an arrangement where he had his bank debit card with him and he would text and ask me to pay in some money every few days. He got through a lot of money but if he'd lost his card or cash it wasn't the whole of his spending money gone. We also set up the Barclays "Pingit" system so if he lost his bank card I'd still be able to get money to him.
He texted me daily so I knew he was OK and one of his friends had my mobile number in case of emergency or him losing his phone. Obviously you need to let the phone company and bank know the dates of the holiday.