The Opening Chapter of Book 6

[Jim Ferer]

No: HPFGUIDX 104953

Britt: "I actually think that Filch is the most likely candidate for
realisation of some "late in life" magic ability. If Hogwarts comes
under any sort of peril in the next books, then he's like to be in
close proximity to physical danger, and those Kwikspell courses may
have actually been able to teach him a thing or two. Who knows, maybe
having Filch doing a bit of magic might make him even seem somewhat
sympathetic?"

Making Filch the late bloomer doesn't serve any literary purpose,
though.  It's neither here not there if he's really a wizard or not;
and if doing a little bit of magic made Filch more sympathetic, than
Draco should be downright adorable.

My money is on Dudley or Petunia.  There's magic in their ancestry,
and Dudley especially being a wizard would really turn the Dursley's
world upside-down, not to mention Harry's.  Not much doubt which house
Dudders would find himself in, is there?

Jim Ferer, who isn't certain he wants to know.