Stephen King : "Rainy Season" question

I have an odd little question about this short story from "Nightmares and Dreamscapes", and I think it's page 364. Towards the bottom of the page, while John Graham is trying to open the cellar door, he thinks(paraphrasing)...he wonders if his mother's other children had lived...what could he mean by this? Unless I'm thick-headed(a possibility)he couldn't mean his OWN mother, as that wouldn't make sense. I'll appreciate any comments to this goofy inquiry.

It says 'wondered if his mother had kids that lived'...I think it's just a funny way to say that the guy was being stupid with the cellar down and not trying the other way to get it open...so he thinks it is a wonder he lived this long with being that stupid...weird way to say it, but that's my take on it.

interesting take, and maybe it's what King thought.

I think it's just an old insult. I remember in Stand By Me Teddy says to Vern "did your mother ever have any kids that lived?" He's just applying it to himself because he's being dumb

I've read "since Hector was a pup" from a few of King's stories, whatever the hell THAT means.