The mother needs to go to court and get a court order so the babies can't be removed from her. The American laws are weird surely no court would allow the intended parents to rock up a year later and take the twins from the women who has looked after them.
It's not that simple in the USA, I don't pretend to understand all the legal nuances but basically the laws and surrogacy contracts are heavily weighted against surrogate mothers, precisely because commissioning parents want to be guaranteed to get their baby.
I've been following this case on Tiktok too, I think because obviously there is a legal process going on, she isn't posting many updates at present.
But this isn't the first such case by any means, I have seen several in the news. Obviously covid caused a few but I don't think that is the reason why this commissioning parent hasn't rocked up to collect.
In USA when babies are born contracted by international parents the baby will automatically have citizenship, and immigration laws mean the parents will have rights thanks to their baby. So it is not uncommon, especially among Chinese, to have babies for citizenship reasons. I'll look out an article I saw that explains it better.
Meanwhile there was another baby that was with a "nanny" for over a year before his Scottish parents collected. There was talk of covid and difficulties with paperwork, but I don't buy it, British citizens who have purchased babies abroad don't usually have too much difficulty bring the baby home.
And at the start of the Ukraine war when there were news stories about surrogate born babies in bomb shelters, there were film shots of babies that clearly weren't newborns, about six months by my estimation - why hadn't they been collected?