Our grocery stores here carry goat milk. I've never bought it but have seen it at
Wal-Mart and Kroger, the milk's in a can and I believe it was over by the baby section.
I found these bits of information doing a Bing search on what baby squirrels eat:
"I found a baby squirrel and I have been taking care of it for about 5 weeks. we found it when it was only 2 weeks old and it was so dehydrated when we found it. but now to is doing great! For the first few weeks (new born- 3 weeks old) you feed the squirrel kitten or puppy formula 7cc every2 hours. Then you feed (him/her) (3-6 weeks old) 7cc every 4 hours. Once the squirrel is about 6 weeks old it will be able to eat small slices of avocado and bits of fruit. Around 8 weeks old it will reject the formula so you will have to feed it water and it will want sunflower seeds, peanuts, dried corn, and many other wild squirrel you can buy at the store for a range of 2-6 dollars at
walmart or winn-dixie."
"Baby squirrels eat hard vegetables such as broccoli, sweet potato and hard nuts out of the shell at seven weeks and can eat their favorite seeds, nuts and corn after nine weeks. Squirrels achieve independence between nine and 12 weeks, after learning social skills. The average lifespan of a squirrel is 12 years."
So I take from this, to start with puppy or kitten formula until about 6 weeks, then start to give them the solid stuff they like.
Good luck and keep us posted on how he's doing! A photo would be fun to see too.