It must be difficult to keep the aircraft trim with him being at the rear and to one side. Perhaps it's time that airlines provided extra wide seats, in the mid section, at a premium cost. I bet he stinks and farts a lot as well.
Since the holds are pressurised and heated, he could fly from there? The forward hold of a 747 can hold an estate car, and a flight attendant could pop down the hatch in 1st class with a box of Dunkin Donuts and a 2 litre bottle of diet every couple of hours.
EDIT: Isn't he too big for the emergency exits? (I'm thinking the overwing ones in particular) Perhaps he really shouldn't be allowed to fly at all