I just want to follow-up here so it can help other people or set the record straight for others who said this is not possible. Due to the death of my father (my wife's father-in-law, no blood relation) she was able to get an expedited visa appointment the next day and was approved for her visa at the end of the interview. It arrived in the mail about 2 weeks later, but I believe if it wasn't Christmas and New Years it would've been faster.
The US embassy has an emergency visa application process. You book an appointment through the normal route, then in the portal area there's a link to apply for an expedited/emergency appointment. It explains on this page what information you need to provide. After applying you wait for the email letting you know if you were approved. We were approved, so we then booked an emergency visa appointment for the very next day. She was approved and we just got her 10 year "M" B1B2 visa. I think (hope) this is a 10 year multiple entry visa, but I'm going to start another post to confirm.
So it definitely is possible to get a visa very quickly to the USA, at least in our case.