Who Ya Gonna Call?

[lealess]

No: HPFGUIDX 141439

Suppose on the merry horcrux hunt, one of the crusaders falls afoul of
a deadly curse.  I don't suppose the Trio want to sacrifice
house-elves or Weasleys in their quest.  Ron might be willing to give
his life, but will Harry be so eager to see him go? So, who can they
turn to for help?

Dumbledore seems to have trusted one person to help him: Severus Snape.

I've read speculation that Snape will try to contact Harry using a
Patronus message, but it could be the other way around.  The Trio
doesn't really have much experience with Dark potions and curses. 
Hermione can apply book knowledge, but how fast can she identify an
unknown poison or spell?  Slughorn and Lupin have some knowledge, but
they may be as morally dubious as Snape, and at least one of them
would have to be let in on the horcrux secret.  Snape probably already
knows this secret.  Harry has already seen him in action counteracting
a Dark curse and possibly saving someone's life.  And, Harry can cast
a Patronus like nobody's business.

If the HBP's book doesn't have a ready answer for Dark calamity, there
is one person who does.  Familiarity with the Dark Arts isn't such a
horrible thing if knowing defenses and cures comes along with that
knowledge.

lealess