Skill transfer & generalization tends to be hard for any autistic person. With an intellectual disability like Abbie's on top of it, it honestly may be nearly impossible for her.
If they'd spent months having her do place settings on the island for every meal, and she was able to do it independently, they could probably work for a month or two every day to transfer that skill to the dining room. I don't think it's outside the realm of possibility that she'd be able to do it - the key is, though, that it would require a lot of repetition every day for weeks or months at a time, and they'd have to work on it with her every day even when the teacher isn't there.
So, yes, it's total bullshit mixed with no way in hell. He expects the teacher to make it happen over the course of a few days with their only involvement being vlogging the process and the miraculous "result." It ain't gonna happen.
It is abundantly obvious to even the most casual viewer, that Asshat and especially P do very little when it comes to working on things with Abbie. They don't want to because it would interfere with what they want to do or feel like doing. Like you said, he expects the teacher to do it. He expects Abbie's therapist to do it. He always makes the argument that he knows what is best for Abbie because he spends the most time with her. Yes, he DOES spend the most time with her, therefore he needs to be putting in more work, if not at least equal work to the teacher and therapist. Not less than they do.
It also feels like he puts the blame for lack of progress on Abbie. Makes it her fault. It couldn't possibly be that because of his and P's lazy asses doing next to nothing that Abbie has regressed and declined, eh Assa??
Our kids have trouble generalizing skills learned in one area to the next area. Honestly, it seems that they took away her template too soon. She should have first mastered that with no prompts and then moved on to fading it out. There's no reason why she has to learn this quickly. Our kids are not on our time table for learning things. They are on theirs. Blazing through each skill and then not practicing it very often will just cause her to lose it quickly again.
That makes complete sense.
Asshat will admit that Abbie used to do something and then stopped. But he won't admit that she stopped because he and Cillame stopped putting in the work. It would be embarrassing to say "Cilla and I got too lazy with things and that caused Abbie to lose or decline in her abilities.".
Like I said before, Asshat tries to put the blame on Abbie for why things haven't worked out. Not that he started a bunch of things, tried it like three (sometimes four) times and then just gave up on it.