quick sketchie; I can see Korra asking Tahno for theoretical lessons on the finer points of waterbending for sport, even without his ability. She’d do it to help him realize the skill is still there, that his knowledge is still useful, that /he/ is still useful. Or /maybe/ she’d have him move in to Air Temple Island once his money runs out, in the spirit of Asami.
YES. HEADCANON ACCEPTED.