Hi MB,
I flew to Switzerland in January and France in March and I wasn't charged any extra airport tax when I flew out the UK on either occasion. I think when I was looking at flights online some companies (think the more budget airlines)explicitly added an amount to the price of the ticket due to carbon emotions, and I don't think it was as much as ?60... more like ?10-?20. However this was just part of the ticket price, and not something extra to be paid at the airport... so if he's already bought the tickets then he should be fine.
Hope that helps
