some lube oughta patch him up. Rough skin contact (little hairs, or shaving stubble) can severely irritate the penis.. Making everything a little moisty should do the trick.
id still try lubricant if you havent as this might help with the uncomfort. im circumsized so i dont have much info on the matter but lube might help. at least until he is comfortable without it
He just makes his foreskin slide back up... as in, he has an erection, and the foreskin slides back past his penis head, so he makes his foreskin slide back up to where it isn't behind/past his penis head.
what do you mean fixes it? is there any way you could "fix it" as you perform whichever act it might be? it might also be possible that there is no moisture and a bit of lubricant such as KY might help. ky works wonders if you ever have any discomfort yourself also so its useful for both parties involved