According to the article they don't know if the bear is dead or not, shot at it numerous times with multiple weapons
The ice axe didn't even register with the bear, it didn't try to peel it out with a paw, it didn't stop or even slow down

I'm certainly not knocking the guy for burying his ice axe in a charging by bear, but I think he just got under the hide not through the skull.
The thing that amazed me the most was the gal and male clients had a big grin after the incident, while the guide, does not

The guide knows....