Hi Karlin,
If he won't do the enema, then he really needs to make sure that he flushes his bowels out well, so that no stones get stuck. I would make sure that he understands that this is an important step. Is he willing to get a colonic? If not, then he has to be sure to use the Epsom Salts both days or a SWF (Salt-Water-Flush) on the second day like Hanna suggested.
Good luck to both of you!