If someone is overweight because of a medical issue, they should be entitled to a second seat at a reduced fare, but if it's a case of gluttony, then the going rate per seat and mandatory 2 seats.
Providing the large man is a glutton, he should have been the one standing in the aisle. that would have provided 7 hours of much needed exercise. If it was a genuine medical condition, he should have been sold 2 seats.
Oh, and the airline should have fully reimbursed Mr Berkowitz.
Either that or airlines need a full rethink about seating allocation and we all know hell will freeze over before that day arrives.