Squirrels can be funny and tricky little critters to raise. That's why I knew I wasn't going to keep the babies I had, but insisted they go wild. They have (as I've heard) a very sensitive system to lots of things - corn making them hyper and mean is one thing I've heard. I've also heard that many baby squirrels can be lovely pets for the first year or two, then hit full puberty and get very mean.
My old boss that did rescue, had a lovely (and very gentle) 4 or 5 year old female fox squirrel that some one gave her for rehab. The woman that had raised the squirrel all these years, accidentally gave the squirrel some pecans that had gone toxic (they had been stored in a plastic bag, gotten warm, and sweated in the bag - turned rancid quickly). Anyway, a small amount of these pecans sent the squirrel into a seizure, and the back legs became paralyzed. So my boss took the squirrel home, and she has had it now for the last 3 years. It's still gentle, but lives in a cage outside.
I don't know....... just sharing stories. :)