I read that he should skip caffeine all the time except right before BD. I heard the caffeine actually makes the sperm more lively. But that's only RIGHT BEFORE BDing.
my dh drinks caffine like its wter and the docotr has told him that he has super sperm so i really dont think that caffine has anything to do with sperm count. good luck
i've also read that caffeine intake helps with sperm motility. of course too much of it will adversely effect the rest of your dh's health, which in turn would effect his sperm.
back in general, but had a larger intake in the days preceding O, you'll probably be fine. (and he won't need to experience the nasty headaches associated with caffeine withdrawal)