Welcome to FT!

This topic isn't off limits for FT, and this is generally the right forum for it.

However, this topic has been debated ad infinitum here as well. I'd suggest you do a search on a word like "overweight" that's unlikely to show up in other contexts. You may find the answer you need there. If not, you may find that your question has become more focused.

Keep in mind, though, that many of those threads have been closed to further posts by the moderators after they degenerated into insults and name-calling! This topic can raise heated emotions, both on the part of those who are wide, for whatever reason, and those who have been seated in your friend's position.

Also, airline policies vary. The only commonality is that anyone who needs a seat belt extender is not supposed to sit in an emergency exit row. Once you find out what airline your friend was on, you might search that airline's forum as well.