My husbands semen analysis revealed a 5% motility but 25 million sperm volume. Can IUI work for us? I have no female fertility problems.

Sure. I had a patient once whose husband had a count of 400, 000 per cc with motility similar to this. She achieved four pregnancies using IUI with me. It only takes one sperm to achieve a pregnancy. Don't give up. Ever.
IUI & poor SA. You need a minimum of 1-2 million live sperm to become pregnant with an iui. With 5% motility & 25 mill sperm you will obtain recover only 1.2 million sperm. So it is possible to conceive, but it will probably take several cycles. Ivf with icsi would to the next step if you didn't conceive after 3-4 cycles.