I agree. The hole in the back of his head is an EXIT wound.
PERIOD! END OF STORY! Shot from the front.
The hole is in the top right of the head, not the back. It comes from the pressure wave created by the bullet causing the head to explode. It isn't simply opposite the bullet entry.
There's is a ton of available evidence, real evidence about this. Things like this are just ignoring it all to stick with some preconceived notion.