Because she'd have had exactly the same experience as other people who tried to step in on similar situations: 88% of the childcare would be dumped on her regardless of what she was doing, and the other 12% would be her trying to cope with Kelly's strategic meltdowns that she's stealing Kelly's kids away. The end result is the sister doing all of the grunt work while Kelly becomes the 'fun aunt'.
I see it a bit differently: my hunch is that Kelly would take any unasked-for intervention on the kids' behalf as a negative judgment upon her ability to raise her own kids, and react accordingly. Because, to Kelly, it's not about ensuring the kids' well-being; it's about protecting Kelly's fragile ego, and she will go to insane lengths to do that.
Narcissists can blindly neglect the shit out of their own kids—sending them off to school in dirty or ragged clothes; never establishing a proper bedtime; packing them hasty, inadequate lunches (or making the kid do it at too young an age; see: Ruby Franke); letting their hair go unbrushed so long that it mats—but the second someone steps in and tries to remedy the neglect,
they're the bad guy, the one who has all the issues, and a judgmental busybody who is just trying to make the poor, put-upon parent's life harder.
They'll also put blame for the signs of neglect onto their kids: "She likes those ratty old clothes, and insists upon wearing them, even when they're dirty," "He pretends to be in bed, but sits up and plays video games all night," "It's their responsibility to pack their own lunches, and tell me when we're out of the kinds of food they need," "I keep telling her to brush her hair, but she does a half-assed job of it."
In Kelly's case, she probably blames both their "neurodivergence" and her own self-inflicted "disability" for why she can't do certain tasks: "She has sensory issues, and can't stand having her hair brushed; it's a struggle every day, and I just don't always have the spoons." However, if somebody was to offer to make sure the kid's hair got brushed (or a proper diabetic diet got followed, in the case of the other one), I'm convinced Kelly would resist it and refuse, and if she did reluctantly accept it, she'd end up being so critical and defensive toward the care provider, they'd stop.
Kelly crying about how she'll be away from them for more than 2 days is weird too. Like, they are staying home. How is this an issue? Controlling narc shit, I assume.
Yeah, it's controlling Narc shit. Everything might go well in her absence—perhaps even better than usual, since nobody will have to be walking on eggshells—and family members might realize that they don't really need Kelly's mostly-useless self around. Having grown up with a Narc parent who was occasionally gone for a couple of days at a time on scheduled trips, I can tell you that those days were a
huge relief, and the rest of our family looked forward to them. The Lenza household might feel a similar weight off of their individual and collective shoulders, given a couple of days without Kelly. And I think that's what terrifies Kelly, whether she realizes it or not.
One of the fears she has expressed as a result of her battle with Long
Fatness Covid is not just becoming too sick to take care of her family, but also her family deciding she was useless and they didn't need her. For her to be absent for a couple of days, and for everything to go just fine? That, to Kelly might be seen as proof that she's not really needed, and if so, that scares the shit out of her.
