Earn degree, rehab, come back, try to increase stock.
I don't think he has any chance of NFL with his career being what it is so far and coming of ACL.
Makes sense he would want to play again, earn a master's, keep scholarship, have support of BYU for rehab.
Unless he is done with football AND not interested in a Master's, seems like staying is clear choice.
Or if he thinks his NFL potential is at peak. . .