Here's what you should do:
1. Contact a wildlife rehabilitator or veterinarian specializing in wildlife: They are equipped to handle delicate situations like this and provide the proper care.
2. Keep the squirrel warm and quiet: Place it in a small, secure box with a soft towel and a heating pad set on low (never directly on the squirrel).
3. Do not offer food or water: Trying to feed a dehydrated or weak squirrel could be dangerous.
4. Avoid handling the squirrel excessively: This can cause stress and injury.
Remember: Wild animals require specialized care. Attempting to treat a half-dead squirrel yourself can be detrimental and may cause further harm.
Here are some resources to help you find a wildlife rehabilitator:
* The National Wildlife Rehabilitators Association (NWRA): https://www.nwra.org/
* The International Wildlife Rehabilitation Council (IWRC): https://www.iwrconline.org/
Please act quickly and get professional help.