Hello, Sammie.
This is no time to evaluate your husband's condition. The name of this game is Time and Patience, unfortunately. The hardness you feel is most likely swelling, and that will recede. At three years out, my neck dissection scar is nearly invisible and my shoulder is as strong as the other side and has complete range of motion. But it was certainly not that way at three weeks out (grin). When his infection has resolved, I would suggest that you seek physical therapy for his shoulder and arm on that side. There are some very simple exercises that help tremendously. I saw the PT just twice and then did things on my own. Sammie, your husband will be much, much better than he is now. You will just have to wait a bit. Hard to do, I know, but the body does a remarkable job of healing, given time.
Joanna