More backstory, if it helps: Anita had wandered into that netherworld of having a son who had graduated from high school, wasn’t interested in college, but was still living at home, with mother and son getting on each other’s nerves.
In a less affluent area than the DC burbs, it would be a lot easier for son to get a place of his own on his pay from the sorts of unskilled jobs he’s qualified for, hence a lot easier for mom to give son 30 days to find a place of his own and move out, or else find his stuff on the sidewalk. Maureen rightly points out, “But… he isn’t the one who’s supposed to be teaching you how to be an adult. It’s the other way around,” and in a city where a young guy can find ways to scrape by on minimum wage, this is how the teaching would be done, if it came to that.
(How do you teach your kid to go out on his own, these days? I remember being the kid who didn’t know what to do with that shiny college diploma, and decades later I’m still not sure exactly what my parents were supposed to do to help me know how to use it to become an adult. Other than discourage me from continuing to stay under their roof. Ultimately, we have to teach ourselves to become adults, IMHO.)
At any rate, Kyle (who had been doing a bang-up job playing the prototypical uncommunicative 19 year old, around mom at least) had known Anita’s move from her rented duplex to her new condo was coming up, had been making noises about moving in with some friends but had been less than clear about it (but had indicated that he wasn’t going to come along to the new place), had refused all maternal help in finding a place of his own (IIRC), had been spending increasing numbers of nights away from Anita’s without entirely moving out (or moving his stuff out at all), and…well, if you’re the mom, how exactly do you get some closure here? Is this business going to just drag out indefinitely somehow, or what?
Apparently we have closure. Kyle seems to have landed somewhere else, and is attempting to make it without Mom’s help. This is good for all concerned. Understandably, Anita was reluctant to force the deal, but at least her move created a situation that made Kyle choose to get out for real. But it wasn’t a given that it would play out that way. Hence Anita’s relief.
There are no rules for this. There is no parents’ manual that tells you how best to push your child out of the nest when he needs to be out, but it isn’t clear how he’s going to make it on his own. So when one stage of it somehow just works out, I think a parent is entitled to feelings of relief, and even celebration. And I think that’s what Anita was trying to express here.