I think he finds one thing and focuses on it too much. Mako and Bolin are supposed to be the new Katara and Sokka but he's barely mentioned them. I don't even think he remembers Bolin's name and the only reason he remembers Mako is because of the real Mako lol.
Ironically he immediately remembers Tarrlok. That is very telling considering where the story goes lol.