you may want to see if you can get a second opinion, as we are in a similar situation, male factor and low count other stuff is pretty good, and we were told that we were better off going for ivf with icsi.We were told by two different docs, that this offered us the best chances, and I was hoping to be able to try iui, but it didn't work out that way. The other question is are they going to give you drugs to stimulate you as well? As that could be why they are suggesting to go that route first.
get him onto a good multi vitamin and maca, maca will increase sperm and mobility, you can get it at health food shops and he should take the max dosage :)