I am glad he survived. Bear spray or sidearm, aside, he acted in a survival mode and it worked.
From the articles I read, it didn't sound like he hit any of the bears when he fired off. Maybe the loud sound scared the bears off. Which, in this scenario, probably prevented his death. Imagine trying to dig bear spray out while getting chewed on. No thank you!
This could go to show that it doesn't matter what side are you carry as long as it is loud

Just throwing in an additional thought.