I need Muriel to give Crowley a hug, actually.
They learn from books and movies and tv shows, they talk to Nina and Maggie, they go native rather quickly because they're just completely immersed in it.
Crowley is miserable, of course he is. He refuses to talk about it, refuses to even mention Aziraphale, refuses to explain why he didn't go with him. Most of the time, he curls up in his armchair by the window and watches life go on around him.
One day it's particularly bad, he goes for a drive that lasts several hours, and when he comes back to the bookshop he is drenched to the bone because he refused to seek cover from the rain and just stared at the sky for ten minutes.
Muriel stops in front of him and says "I'm going to hug you now" and then does exactly that. It's a bit awkward since neither of them has actually ever properly hugged another being, but Crowley couldn't resist if he wanted to. He melts into, all long limbs and pain, and Muriel holds him without a care for their clothes and doesn't say a single thing the entire time.
They cling to each other for an hour without tiring, and Crowley takes off his glasses at some point and properly hugs them back. Aziraphale is- was his world, and without him, he is aimlessly drifting through space, and there's nothing anyone could do or say to give him the gravity he is missing.
Muriel is an anchor, kind, understanding, and without centuries of history stretching between them, so he allows himself to be centred by them while he figures out how to create his own gravity again; how to make a star that can exist without its twin, free to hurl through space all on its own.