I would have your dh try the antioxidant protocol for 3 months & re-test. I wouldn't cycle or make any decision until then, as that protocol has helped some of the men. I know 3 months seems like a long time, but if it works, you've eliminated the need to make what is a major decision re. donor sperm, cycle costs, etc.
The are several variations, but here is the one Kacee's dh used, which I saved, & it did work for him.
500mg of Vitamin C 2x/day
400mg of Vitamin E 2x/day
Pycnogenol 100mg 2x/day
You can get Proxeed from Freedom Drug, & Pycnogenal from a health food or supplement store.