Not that I'm aware of (as a MUST) but I think they are the only company flying into Briain that offers flights return from Banjul and your friend will need a return ticket (I think!).
Yep a return ticket is a must. A direct flight from Banjul is your best option. Avoid any transits as that might proof a difficult undertaking. He may not be able to travel if the transit time is beyond a certain number of hours. Its usually accepted around 4 hours.
“When I despair, I remember that all through history the way of truth and love have always won. There have been tyrants and murderers, and for a time, they can seem invincible, but in the end, they always fall. Think of it--always.”