Not only is he a bad owner, but a dumb one as well. Why the hell would he think a Reimu would eat something spicy?
Not only is he a dumb owner, he threw out a gold badge Reimu for eating a snack. What did that set him back, a dollar? Put her in her yukkurium and send her to bed with no dinner. Srsly, does this guy like wasting money?
That aside, yes, spicy food would have killed the Reimu, and he's gonna be without any pets when his Meiling steals another snack.
Here's hoping that a kind mister or miss rescues Reimu...
I would, but I don't live in that yuniverse.
Knowing this artist/writer, the answer is no, and the story likely ends here, or possibly continues and makes the Reimu more miserable before eventual death.