A few reasons that lead me to think the video is fake and that he actually bought a J ticket:

1. As mentioned above, the crew could’ve moved him to a bulkhead or heck even PEY
2. The crew kind of played along - J crew smiling at the camera, HKG ground staff wishing his ankle well in the end
3. The guy sleeping next to him in his J seat looks 90% like his father (I follow him on Instagram, his dad is featured in many of his posts)