Can I claim him?

I've known for a long time that Johnny (4 yrs) has a great imagination. Since he could walk and talk he would regularly be some character from TV of some random animal. And it was always required that anyone else only address him as his "character" if they desired a repsonce. This love of pretend play has continued and he loves to "play movies." Last Christmas I walked past the boys bedroom and over heard a reenactment of an entire sceen from The Santa Claus word for word. But this latest development is a new one to me...his imaginary friend Jerry.
Now he will even tell you its his imaginary friend so no need to worry that I need to rush him to the shrink or anything. And I'm fairly sure we know what has brought this friend around after Johnny told us, "Jerry always plays whatever I want to play." This is of course the exact opposite of his brother who only likes an idea if its his own.
But itis amazing how annoying a person we can neither see or hear can get. Johnny regularly talks about him until we all feel like jumping in front of a bus. But what I want to know is, he's been at our house since Sunday...and if he doesn't ever go home, ya think I can claim him on our taxes next year? :)