Oh! For a fact, GoPro Hero 5 is waterproof (WITHOUT a housing) upto 10m. I have had my Hero 6 in water many times and it stood up to it. And the build and design is a replica of the Hero 5. Take that baby swimming, buddy.
Regards to your bear bear colleague :)
Oh! Okay... Cool... It was this youtube post I saw yesterday that was gonna get me in fears
So, wanted to be double sure...haha.