Sounds like actinic keratosis. Does he have pain or itching such as fingers touching or pants rubing against it? If so let me know i might have info on this if you can describe any sensations or reactions he has.
he said it itches sometimes and his pants and socks seem to irritate it.
Does it itch, burn or sometimes sting? I just read something on parasitic infections... how long has he had this? Also, could it be a garden variety wart? It reminds me of a wart. Go get that shit removed and biopsied.