Ah, well, there's no worry about that, we can just award him the one BP, I'm sure he won't mind taking down another to reach round two.
No tone, just trying to be clear. XDD JEEZ YOU'RE SO HIGH-STRUNG!!! :P
There's no "5-3" rule; it's an "if you're up by two rule." If there is a disconnection and there is somewhat of a disagreement between the two parties, as in not having a rematch, whoever was up by 2 would be considered the victor.
If of course a match came as close to 2-1 and there was a disconnection, I'd also have to consider awarding the win to the person up (however that 1 Pokemon could be in the midst of sweeping, so who knows? We'll come to that if it rears it's ugly head.)
So yeah, it's an "up by 2" rule, not a specific number. You said it yourself, you were down 4-1 and came back to win. Of course we're disregarding that here: desolation shouldn't have started the match if he truly and honestly "had to go". He could have done what Alex did in a match awhile back, consistently VM'd his opponent and ask for a postponement if he HAD to go.