There are some that say that EVERYONE will be in the presence of God in the end. And quote scripture as well. BUT - for the unsaved, it will be the type of presence that would strike down people back in the OT that looked upon God.
It will be His presence reminding you everyday of the sins you committed, the folly you followed, etc. I have no idea - but I can see where that would be eternal torment. Like one’s spouse constantly reminding you of every little mistake you ever made.
It would be a real hell to base one’s entire life on something, and then always be reminded how wrong you were.
Hopefully he did have a deathbed conversion.
I’ve often thought that heaven/hell may be a matter of degree. Where the torment is the amount of separation your have from God in Heaven. The less sin you have in real life the closer you end up to God in Heaven. Acceptance of Christ is the cutoff of where the pain/no-pain threshold is for eternity. Imagine you learn that God is there and you can get no closer for eternity....could you imagine the desire/impact/guilt you would have.
Atheists would be be only less further away than satanists or vice a versa... arguments could be made.