At this situation, it's better just give him one rather asking whether he need one or not, gudako.
I wonder if Gramps knows how to read this?there...I've got a kanji that I'd like to know how to read!There's a red mark over...Ah...Umm...Need a pair of glasses...?I... is that so...?This kanji... I don't know how to read it...So-calledGramps!No need for that.