Severus is no good with sick people. This should not be surprising to Harry.
Somehow, though, he'd always thought that it was just part of Severus's personality. Comfort being something he couldn't be arsed to do. Especially since Harry had brought it on himself. Why he ever thought it was a good idea to go on that pub crawl with Ron and Seamus was a mystery for the ages. Or at least until the next time, anyway. It just had honestly never occurred to him that there might actually be something that Severus couldn't do.
Sacrificing his guts yet again to the porcelain god, Harry has some major doubts about Severus's comforting abilities.
"Where the hell are you?" he shouts, in between heaves. "Get in here and do something!" What, exactly, Severus can do about the situation at hand is an unknown unless he is somehow about to spontaneously invent a fabled, but entirely nonexistent, sobering potion which would really come in quite handy about now. Although standing around and looking helpless would be an improvement over the current state of affairs.
Well. At least he thought so until Severus does just that. Looking like he's never seen vomit in his entire life, he leans against the counter, eyeing Harry with something that might be fear, might be horror, but most certainly is not helpful concern. It's not even malicious glee, which Harry has to admit he anticipated.
"Forget it," Harry breathes. He tries in vain to keep the rest of his internal organs planted firmly where they belong, and is quite shocked by their recalcitrance. He rests his cheek on the inviting coolness of the toilet seat and prays for death.
Despite a rather impressive number of previous attempts, Death refuses to show, even for its master. Inconsiderate arsehole.
The only sign of the other inconsiderate arsehole is cold fingers brushing against Harry's exposed wrist, circling, comforting.
Apparently Harry's lack of faith in Severus's comforting abilities was premature, though he's not ruling out an appearance by Death ....