Andthank God she was there, for I was filled with that icy dreadagain. Everything I did seemed awkward to me, and every-thing I said sounded freighted with hidden meaning. I wastrying to remember everything I'd heard about dope addictionand I couldn't help watching Sonny for signs. I wasn't doing itout of malice. I was trying to find out something about mybrother. I was dying to hear him tell me he was safe.
From this passage we can see the narrator keeps looking after his brother for fear of him being trapped by drugs again ;the theme of the obligation toward brotherly love.