'You could be happy. I hope you are.' from "You Could Be Happy" (by Snow Patrol) a song that really speaks to how much you hope someone you cared about deeply is doing well, even if you never see them again and have no way of knowing how they are.
To think I might not see those eyes make it so hard not to cry. And as we say our long goodbye I nearly do. Light up, light up. As if you have a choice. Even if you cannot hear my voice, I will be right beside you dear