ALexander an orphan, period alcoholic and then eminent neurosurgeon,  suffered a violent form of bacterial meningitis that attacks the brain causing a 97% death rate.
Following a week of lost consciousness pumped full with antibiotic and other drugs he very unexpectedly recovered.
Returned to consciousness A describes in his book his very intense Near death experience (NED) in very flowery poetic terms;-

“spinning melody”
“realm of the earthworms Eye View”
“Green brilliance of the gateway”
“Black but holy darkness of the core”
“Guardian Angel on the butterfly wing”
“I understand I was part of the divine”
” the loftiest dwelling place of the almighty creator”
Full marks for poetry but proof of God????
NED,s all describe an intense, blissful, colourful experience. (But so very  different to a strong LSD trip??
A choses to call the particular intensity of his NED trip proves the existence of God. But the only basis for his claim that it was God is that the regular brain scans during his coma showed that his neocortex was out of action so the experience could not have happened in his brain and therefore must be God.
 I have no squabble that A choses to label his NED as coming from “God” if he wants. But to argue that his NED proves the existence of God and heaven, is like saying BFG proves the existence of giants.
An interesting sideline; as a scientist A points out that all particles protons, electrons, neutrons each one is connected to every other one in the universe (all research tends to produce the result wanted by the researcher Some mediums such as, Steve Smith claim to pick up messages to and from  distant people) One day as we have discovered radio waves that transmit coloured pictures from  Australia, we will discover these as yet unknown waves out there. But again he existence of some as yet unknown wave hardly prove the existence of heaven and God,