You may get lucky, Molli may realize that Sam is not feeling up to par & she may leave him alone.
Just in case though here's a few ideas that may help keep her more calm & away from Sam.
Give her an extra walk or two each day while he is recovering, that will help wear her out. An extra game of fetch each day or the like. Even some obedience training & the like will wear her mind out. Actually mental activity wears Kaige out more than physical activity.
Give them some filled Kongs, buster cubes, etc....
Make sure Sam has a little "safe place" a nice bed in a crate or corner, or even have a baby gate on hand or the like so you can seperate them in different rooms if need be.

I wish Sam the best of luck at his vet app. today. Please let us know how he does.