Commas and Parentheses (Not the Usual Question)

Hello,

I'm sure you're all sick to death of answering questions about the placement of punctuation inside or outside parentheses and quotation marks, but this is a slightly different matter.

I was happily (or, rather, manically--it's due tomorrow morning,) writing my term paper tonight when I started to wonder about a point of grammar. It's what I did above: putting a comma at the end of a long parenthetical remark, inside the closing parenthesis.

For example, from my paper: "It is impossible to know whether Cross knew of Eliot's third and fourth brothers, whom he does not inclue in the roster of her siblings, but Eliot (though little more than a year old at the time of their birth and death,) likely would have." OK, I know that's kind of wordy for an example, but it's nearly one AM and I don't have the mental energy to come up with a sentence of more appropriate length.

How extraneous is the comma after death? I assume this is a question more of style than a hard and fast rule of grammar, but can anyone set me to rights as to what is more accepted? If the parenthetical remark is quite long is a comma more appropriate?

Thanks!

greycat