Spell out numbers instead of using numerals: two, not 2.
I’m just about the last person who should tell you never to capitalize Old Lady (there’s a character in “that novel” generally referred to as the Old Man), but since there’s no indication here that there’s a reason for it to be capitalized (it’s not used as her name), I’m changing it to lowercase.
Did you catch the typo in the second sentence (doe sthe where it should say does the)?
The parentheses in the last sentence aren’t incorrect, but they’re a bit obtrusive, and commas would serve just as well, if not better.
(If you’re a grammar fanatic and don’t care that some people may not even understand you because your grammar is so correct, you’ll want to write the last sentence as Whom, or what, is she feeding? You’d answer the question with She’s feeding them, after all, not She’s feeding they.)
Kudos to the person who created the example for writing back yard as two words (backyard is an adjective, not a noun).
You first noticed her doing it about two weeks ago. She doesn’t have any pets, so why does the old lady bring a tray of food out to the back yard every night? Who, or what, is she feeding?