It is as realistic as that other nature documentary, Sharknado.

In the real story on which the movie is based off, the bear dies pretty much after going on a coke binge. Thus proving that bears can also die rockstar deaths.

Im quite sure the real bear swapped a gambling addiction for trading stock market shares, estranged itself from its friends with mood swings and a sudden personality change, contracted gonorrhoea at a cheap brothel and then died

I think the true story shows you what would realistically happen. There's probably an amount of cocaine that would allow the bear to survive for a while but it's less than a few bricks.