I think the whole “Kings Cross” chapter in the end of Book 7 is perhaps kabbalistically explained (although I have absolutely no mekor for this except for what a friend told me, so don’t quote me!) – Apparently [so my friend says:], Oilom Habo is made by what you comprehend of it in your own unique way. There is no standard Oilom Habo, rather it is made up of the way your conciousness can identify with the things that are Up There, based on the way you lived your life.
That is why everything began with his thoughts, etc. etc. According to that, he was simply in Oilom HaEmes and therefore getting all the answers, and Dumbledore wasn’t there at all, rather Dumbledore was Harry’s medium of recieving a sudden download of revealing information.