There really is only one answer here, and that would be to talk to your airline, or if you've booked through a travel agent, get them to do the legwork for you. Anything that goes on a plane is at the airline's discretion, and the last thing you need to do is chance getting turned away on the day of your flight because you didn't check properly. Hope it all works out and you all have a lovely holiday. Incidentally, I don't know your friend's problem with breathing is, but FYI it's supposed to be be pretty hilly around Valetta. It might be worth bearing that in mind if walking makes him/her breathless.