Good luck supporting him as best you can.
I know of a man who was told his sperm was no good and that he could never have children. Then he told them he already had 2 with his ex wife. They said "those aren't your kids" but he knew they were. Anyway they told him to give up all hope of fathering any more.
So he and his new wife went home and decided to imporve their lifestyles and diets, esp, him. He cut down his hours of stressful work, reduced drinking to light at weekends only, stopped smoking and had fun. Then 6 months later had some more tests and all the little sperms had started swimming again in their thousands. A few fun months praticing and then their bundle of joy was expected and arrived safely and well.
SO DONT GIVE UP HOPE.
Also Marilyn Glenville is a nutritionist who specialises in fertitily health and problems. www.marilynglenville.com may give you some useful ideas and she has a book all about fertitliy you could buy or request from your local library. She also has mens multi vits for fertility. I think zinc is important from memory.
Good luck,