Q.saving tomatoes from savage squirrels
My mom’s tomato plant got attacked by squirrels. There were exposed roots and most of the plant is really brown and looks dead. Some is still green but it’s not connected to the roots. I was wondering if I should cut the green off and stick it in the dirt, or if there is another way to save any part of the plant.
"Occasionally" if there are enough "air roots" on a plant you can in fact re-root it. This may or may not be an option for your mom's tomato plants.
You could also try some simple pruning off of the dead stems to allow the rest of the plant a chance to continue growing, however as it gets later in the growing season, her plants will have a lesser chance of growing blooms and setting fruit.
Either option -- or both -- is certainly worth a try. Your mom really has nothing left to lose at this point, right?
These articles will give you additional information about how to approach a decision and then how to act on it:
https://www.gardeningknowhow.com/garden-how-to/info/reattaching-broken-stems.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/should-you-prune-tomato-plants.htm