Responses
Fingerprint identification may still be an issue, though... (every time she needs to use her fingerprints to prove her identity) and same with DNA identification (still needed if one of them becomes an unidentified victim or gets accused of a crime): seems identical twins have both non-identical fingerprints and non-identical DNA, when compared to each other

I hope the EX gets with the sister when she wakes up.
There’s no reason the sister should have to die in this story. They are a good couple and they deserve to be happy even if she doesn’t get her body back!