What Tahno needs right now is tough love.
Somebody to bust into his room in the morning and yell “GET UP SUNSHINE, YOU HAVE A A PURPOSE AND A DAY TO FULFIL”
Somebody to force him through the day, refusing to let him fall into a slump of self-pity and bitterness.
And that’s where Korra comes in.
Of course, he would hate every minute of it,
but he’d definitely thank her in the end.