If your Arsenal-supporting friend sincerely believes that a rival World Cup would go anywhere at all, then they're a little bit naive and don't really understand the game. Qatar could end up being (more of) a catastrophe, and heads may roll at FIFA but the FIFA World Cup isn't getting replaced any time soon.
Ah sorry I did not get the "size 140" reference, it's in a sizing format I'm not familiar with!
As a former-kid who had his own dreams (Scotland winning the World Cup) which have had to be progressively scaled back as I grew up (Scotland qualifying for the World Cup) I sympathise, and I hope your Arsenal pal gets to see the tournament they dream of :)