Beginning Today, My 16 Month Old Nephew Screams In Apparent

Beginning today, my 16 month old nephew screams in apparent pain when anybody goes near his scrotum. There's no redness or swelling. I cannot palpate either teste, but his mother says she's felt them before. I also felt around for perhaps an inguinal hernia, I didn't feel anything. Should she be emergently worried? Also, he doesn't display any sort of discomfort when he's walking around or playing. She also says he's urinating normally.