GUEST, with respect, your great-nephew aged sixteen doesn't need an intellect, he needs some manners. One of my neighbours has a similar child of 9. This girl thinks it's acceptable to answer everything with a grunt. ("How was school today?" "Ugh" "Are you going swimming this evening?" "Ugh" etc etc.) I finally decided to be blunt with her. I said "If you can only grunt at me, I don't want to talk to you any more. Cheerio!" and went indoors. I don't bother with her any more.