imaginary friends

He probably understands that Jack isn't real, although he may INSIST that Jack IS real! When I was a little kid I didn't really have imaginary friends, but I did believe that my stuffed animals, blanket, dolls, etc were real... but on some level, I always knew they were NOT. I mean, they couldn't really move or talk... it was just me, pretending and wishing! I would say, humor your little guy. You may even want to try tape recording your son telling the stories of his wild adventures with Jack! As your son gets older and makes more "real" friends, Jack will probably slowly fade away... and you might even miss him!

Oh, I definately wouldn't worry about it. My nine year old had an imaginary snake when she was 2. She would carry it around in her little hands and set it on the table while we had dinner. And she said it talked to her. She named it "Snakey." Snakey disappeared when "George" showed up on the front porch. SHe was 4 then and george was a 10 year old boy from Jupiter. He was born and raised on Jupiter but he had an aunt a cousin that were living in the rings of saturn. When Brooke started preschool, she started leaving "George" in the car when she went in. by the time she reached Kindergarten, he was gone. Let him go on with it. Even play along sometimes. He'll grow away from "jack" before too much longer. When he does, I guarantee, you'll miss Jack.

Totally normal and a sign of a great imagination, let him carry on. If he starts to blame things on Jack, when he gets in trouble, I would nip that in the bud. But encourage the stories and ask questions to encourage him to build the stories or to draw pictures of the adventures he has with Jack.