heard my son's dirty conversation with his friend

the other day, I was putting up laundry and I walked by my son's room and overheard him talking. he was on the phone with one of his buddies saying I hope (not saying her name) will like my dick.then he said I think it's tiny. he said it's 3 inches and his friend was like mine is 5. I had his father talk to him about the situation. it was very weird and awkward. Now he is asking his father if his size is normal. is 3 inches a normal penis size for a 14 year old?