I think there's one out at London Luton airport that's open to the public.
If you're not dead-set on a passenger jet, you might find more availability in a Cessna sim at a flight school. They do have some that are full-motion. He's probably more into the big jets though if he's into X-Plane/VATSIM.
If you're flying on points and distance isn't a problem, there is a 737 simulator at the Delta Museum in Atlanta, on the grounds of their corporate headquarters.