Sperm count booster?

My fiancee did one of those at home sperm counter tests and it came back that his was low.. He was a really heavy drinkers for a long time but now is a year sober. Whats something he can do to help boost his sperm? We are checking out fertility doctors as well but the more at home boosts we can try the better so is there any ideas anyone might have as to what he can do?