Yes, it's odd that a grown man would care about who has more IG followers.
I can't ever imagine being concerned about something like this.
To each their own.
Yes and no...
Yes, because it's a pathetic marketing game.
No, because it brings him business. I've talked to multiple successful PTs/coaches over the years and all of them get most of their new clients via social media. This goes for most services or products, most potential clients start their 'journey' with some Googling, Facebooking or IG-ing.