Well, I did not crate rest at all, I wanted her up and moving immediately and started doing range of motion exercises the day after surgery. I did range motions while she laid down, I moved the leg front to back like she was walking. Did this ten to twenty times 3 or 4 times a day. I let her do whatever she wanted and encouraged her to walk and move around.She had one done, then 12 weeks later the second one, did the same with both legs. I also had a Sheltie with bad HD, did the same surgery and workouts as with the GSD.
Scar tissue starts forming immediately after surgery, doing exercises will not hinder scar tissue at all.What does concern me is that by not moving that leg, the muscles and tendons and ligaments might not be able to stretch out now without pain and that is why he is crying and still taking meds. Now, to make the leg work, the muscles/ligaments/tendons will have to stretch to work right. I imagine they have atrophied and it will take work to get them working.Any pools near you? I would suggest lots of swimming where he doesn't have to "touch" the leg down, but will not just let it hang while swimming. If the water treadmill is deep enough, put him on it and let him walk, he will eventually have to start using the leg to balance and swim..
I think at this point, I would walk and walk and walk and take him up and down inclines and swim him if you can. Its sorta like making a person do physical therapy, its hurts, but needs to be done.
I am not a vet, nor trying to be, just had lots of experience with my own dogs and FHO and plenty of them done at the clincs I work at.