"[…] these are Mother's Day chocolates. […] I was – able to pick them up at a bargain price. [They're] in perfect condition, […] stored under the best of conditions since last spring. All we have to do is remove the purple ribbon that says Mother and we're in business." (4.6)
Does anybody else get the feeling that these chocolates are kind of funky, old, and second rate, in spite of Leon's claims about "perfect condition"? They've probably been stored in some stinky warehouse, melted and re-hardened who knows how many times. Symbolically speaking, these chocolates are unwanted. There are twenty thousand boxes left over. Nobody wanted them on Mother's Day, and nobody really wants them now. Sad isn't it. Poor chocolates.
Well, it gets even sadder. Something else happened last spring, something concerning mothers. That's right. We're told, "Jerry's mother died in the spring" (9.1), and we get a flashback of his anger and grief at her funeral. The loss of Jerry's mother is referenced frequently, and helps keep up the dark brooding Gothic mood of the story. Of course, Jerry doesn't know that the chocolates are from Mother's Day. Only Leon and Archie are in on that little secret. So, the chocolates are only symbolic of her death to the readers. This is an example of dramatic irony, where the reader knows things that the character doesn't.
The death of Jerry's mother and the Mother's Day chocolates aren't actually connected in any real way. But, they are connected symbolically. This symbolism also connects Jerry with the chocolates. Both Jerry and the chocolates have had the word "Mother" removed from their lives. "Mother" is strictly in the past. Now both chocolates and Jerry are thrown helpless and defenseless into the cruel world of Trinity with no "Mother" to protect them from Brother Leon and The Vigils.