Besides all the good advice in the thread, about condoms:

He should be somewhat comfortable with putting on condoms, he has to train that before it becomes necessary. There are plenty of videos explaining it, let him find them and check them out on his own terms. Let him know not every brand fits every man. He will need to overcome the awkwardness of buying them in drug stores or supermarkets, if he finds it awkward at all, he has to get over himself and do it. A possible motivation could be that if girls can buy their period products, he can buy his dick wraps.

I find it very commendable that you think about this problem!