The adoption thing is an interesting idea... Although I'd fear that if they adopted an NT child, Abbie would start phasing into residential care faster than she could blink.
I do feel a little sorry for P sometimes, that she didn't have an NT daughter, especially as A managed to produce one... She's obsessed with Isa. and is all over Summer like a rash. P gives lip-service to loving Abbie, but honestly, while she probably loves on her a level that you would "love" any biological child, I don't think she actually LIKES Abbie very much. I think she finds her hard work and stressful. But I can kind of see where she's coming from... Abbie hasn't got a lot to give back. They would never have a traditional mother-daughter relationship.
I also wonder what would happen if, heaven forbid, something happened to A. There's no way P could cope with her full-time, unaided. I think the vlogs would stop, and we'd hear on the grapevine, within 3 months, that Abbie was living, part time at least, in a care setting. There's no way Isa. would drop everything to come and care for her (and nor should he be expected to), and P just couldn't/wouldn't cope with her.
I've also thought about what Abbie's life might look like in 10 years? Would they still be vlogging a 25 year old, diaper-wearing ADULT frantically rocking on the couch and honking? Who hasn't developed or changed in 10 years? What is forgivable as a child/teen, isn't cute when someone is obviously a physical full-ass ADULT. Obviously Abbie can't help who she is, it's not her fault. But where will she fit into society?