Melinda,a friend of mine did too,with a Squirrel I found in my yard.
When he was old enough,she slowly introduced him to the outside and he eventually stayed outside by his own choice.
Still would visit ever now and then.
Someone I know also raised a Raccoon-baby successfully after his siblings had been killed,yes it's illegal,but sometimes you have to follow your heart and do what you feel is right.
"The cruelest animal is the Human animal"
3 kitties,Rocky(r.i.p my boy),Chico,Vinnie