I learned more on the story of Hugh Glass in a museum I visited today.
The bear was with two cubs, hence the vicious attack. All Hugh could defend himself with was his knife which he thrust into the bear again and again. Glass won the battle but at the cost you already know of. Bridger and Fitzgerald were in the process of digging a grave when approaching Indians frightened them away. They covered the "body" with a bear skin which later would be a factor in saving his life.
When Glass came to he could feel the bare bone of his ribs on his back. He didn't make a raft to float down the river as Indians would see him. This is why he went by land mostly at night. He fashioned a splint for his broken leg and made a sort of carriage for it so as to be able to drag his body.
Many times he lapsed into unconsciousness during his journey. At one time he came to only to find another Grizzly Bear standing over him. He felt the bearskin covering him attracted the bear. He remained perfectly still while the bear flicked off the bearskin and began to lick the maggot-infested wounds. He feels this prevented further infection and most likely saved his life from a slow death.
When he reached the Cheyenne River he felt it safe to travel by water and then fashioned a crude dugout from an old log and floated along the river. This makes his 200 mile journey a bit more believable.
He vowed revenge upon the two who abandoned him but by the time he met up with Bridger again, he was now a man and well known explorer and guide so thought it best to let him live. As for Fitzgerald, he had joined the Army and to kill him would be a crime against the government so had to let him live too.
Why hasn't Hollywood made a movie of this story?