I hope there is lots of Snuffles in the next chapter. Btw not that I mind but in reality A headmaster and his deputy would never be allowed a week away at the same time.
Author's Response: Not normally, no. However, my thought is that any of the Heads of House could be called to be acting Headmaster, because of the way the administration is structured. Thus, both time DUmbledore goes missing in Canon, the Heads divvied up his job.
Here, Sprout is doing most of the hands on medical work with Poppy. Flitwik is taking care of day-to-day administrative duties, and this leaves Snape to oversee things to do with the children who've been found to have evidence of abuse. Writing reports for the Ministry and the like.
He handles Harry's exam because he doesn't trust anyone else to. After sober reflection, he's realized the if it gets out that the BWL was abused by Muggles, there would be murder done.