He crossed over twice, and was reunited with thousands of people he’d known in the past. 

In that higher dimension, he was allowed to remember everything in the memory of our Universe. When he was informed that he was "going back" to 3D, he was asked if he wished to consciously remember all he’d remembered and learned upon his return to Earth.

Michael says, “I said Yes, like a fool! My return was remarkable, as I was not completely back in our world. A portion of my consciousness is still on the Other Side, and in full communication.” 

So he is able to direct questions to "them," and they provide answers.