Well, do you think it'd be smart that he'd get a cell phone in the first place?
There's no, like, "pan-European" cell phone company, and when travelling from country to country, "roaming fees" apply. Which are quite high. The European Commission is trying to regulate these things (and bring down the fees - see
here), but the fees are still really high. You can
easily end up paying 5/$6,50 a minute.
He'd always have to keep track of which country he's in (okay, that should be doable), which cell phone company his card is, which cell phone company he presently uses for making a call... It's annoying, and expensive.
Really, if there is no real need for having a cell phone, I'd say he should go without one. After all, he's travelling in a group, it's just for a couple of weeks, and it's just Europe! I assume they'll stick to bigger cities anyways, so in case he really needs to make a call, a phone should be available without any problem!
(Have you looked into things like
skype for keeping in contact and making phone calls via the internet? I've seen people using this a lot in internet cafés... and you don't have to get calling cards or remember phone numbers or anything. Probably cheaper, too.)
