NO he is not, his spirit is at work in the earth, he himself, his physical being, is behind Christ until he be cast out by Michael......future.
Just as Christ's physical self is in heaven, until He comes after Satan is tossed out;
2Th 2:9 Even him, whose coming is after the working of Satan with all power and signs and lying wonders, ...
If that's past your understanding, so be it, just put it on a shelf and leave it there until you can understand it.
This is like leading a horse to water, one can't make him drink, I have lead you to a truth, I can't make you believe it.