I'm in a similar situation, at the 5 and a bit week point after breaking my colar bone, been confined to riding on the trainer at home. It got real boring at times, but like you I couldn't bear loosing what fitness I had built. But now I am so glad I kept pedalling at home, I'm off for a ride outdoors this Saturday and I CAN'T WAIT!!!!! It's probably a good thing to show your passion for cycling too in this way, so as to increase the chance he'll return to cycling after recovering. Hope time passes quickly over the coming weeks!