Do what thou wilt shall be the whole of the Law.
True, he may very well have gone to his "happy place"... but I am pretty sure given the research on Near Death Experiences, that he saw heaven because that was the image he was raised with and that's what makes him comfortable. What would make me comfortable is envisioning Liber XV playing out... or if I were to have found my chosen and preferred and she were dead, to be reunited with my chosen and preferred. We go to the most peaceful thing we can and given the brain chemistry going on with a dying brain, that's what happens.
We may think it to be real, and to some of us - it is. Much like other types of "religious experiences", though, it's not objective proof to others of the validity of your belief system. Personal experience only really proves the validity of that religion to the person having the religious experience. I invoke all sorts of Goetic experiences but I would never think that this would be sufficient proof for you to believe in the Goetia... I'd recommend going into it for yourself and judging these claims based on your experience. You may pray to a god and I meditate on Knowledge & Conversation of the Holy Guardian Angel... and we may attain communication back - doesn't make it proof to others of the validity of either beliefs.