Ruby
It'll get fixed. Even if he doesn't remember, maybe he'll get used to you and it'll be fine.
Since when do we get parallel folks one at a time, though? Last time it happened, it was pretty large-scale... and it happened to people who were around. Cas disappeared ages ago, why would the seal throw a wrong one at us now?
...right, sorry, asking questions you don't know the answers to. I'm going to get him. I don't know where to take him, though - does him being broken pretty much not an angel anymore mean he can get through the wards, in the complex?