What is this thing called happiness? Are you happy? Am I? Sometimes yep, sometimes nup. I think the question should be "Is he happier having done it than he would have been had he not done it?", and the answer to that is that he had to do it; he couldn't have lived any other way, which effectively nullifies the question of how happy he is about it. I don't think it turned out the way he expected it to. Was it worth it? He made the world an incalculably better place. It must have been worth it, whatever the sacrifice.