I have a lot of sympathy for the guy. Surely he must have been seated for takeoff and landing.
I had a similar experience a few weeks back although no way as bad as that incident.
I was seated in 4F on a Qantas flight from MEL-BNE. The woman next me was obese. Her seat belt was at the maximum length setting. I have quite broad shoulders so I take up the full width of the seat at shoulder level, my right shoulder was right up against the window/wall and my left shoulder was at the edge of my seat. She was pressing up against me the entire flight. I discretely asked the CSM if I could move, but the flight was full. It was the most uncomfortable flight I have ever had, I got cramps in my shoulders. Row 4 has the trays in the arm rests, however she was so big that she could not extend it, so she ended up resting the meal tray on her chest.
Although I have some sympathy for larger passengers it can't be a nice experience for them either, but really airlines should have made her buy two seats or a business class seat.
I was going to complain but it was the flight was the day before the grounding so I thought my complaint would get lost in all the other things going on.