Soldier needs to go talk with the doctor and/or his leadership.
-Straight-up PT failure would be grounds to get kicked out.
-injury needs to be taken care of first, as long as the Soldier follows instructions and common-sense, if he doesn't feel the doctor is helping, get a second opinion.
-if the injury doesn't go away, there would be a "board" that meets to determine if he's still fit to serve. Some can, some can't. Basically if the injury makes him unable to do Soldier duties, he would be separated from the Army, but receive disability pay.
Good luck to him!