Basically, what we're going to do is put his face on a different body (AKA his face on another picture of him.) I don't know why he's doing this, he says he wants it, so... Can anyone give me a hand?

I'm not a whiz at Photoshop, but I can teach you how to do this, the way I do, at least. You have to get a picture of your dad, and make sure his face is in it (duh.). Then, after you do that, make sure the background is transparent (I usually do that with the Magic Eraser tool.). Afterwards, open a new image (the one you wish to put your... dad's head on, as weird as that sounds.). Go back to your dad's head. Copy it, then go back to the other image. Go to paste, and put your dad's head where you want it. ...That's how I do it, at least...

If you know how, use the pen tool. Best thing for this situation. Wouldn't hurt to use burn and dodge tools to modify the lighting to match the second body, either...

I'd do it if you'd let me, but I serious doubt you would.