You are definitely in the right place!
Welcome and thank you for your interesting story about your son and his story from 911. It is hard to believe that these events now happened 11 years ago! I remember being transfixed to the TV screen as they unfolded. It is GREAT to read that these spiritual entities are now being reborn and so quickly after the event. Here is some valuable information to bring you up to speed on everything that has been discovered in the last few years about what it is to be a human being.
What your son is telling you is most probably true.
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If this topic interests you (Life After Life) here is some other information you might be interested to read.
I began discovering this information after watching a very interesting TV show about a young 3 year old boy who remembered a past life as a World War II pilot. I had been aware of the concept of reincarnation for numerous years, but this was the first recorded case where all of the information could be verified by people living today.
It literally changed my world over night with regards to what we are. And what we are seems to an Energy Light Being as our core consciousness residing in a human body to learn lessons during this lifetime. We are all part of a Spirit Group from 5 to 25 members, lead by a Spirit Guide. Your essence / consciousness never dies but is eternal. Not in the religious sense, but as an Energy Light Being that reincarnates over and over again. Cool science fiction stuff!!

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This information is very interesting, not scary at all, and very informative. It may answer many questions you have about your life, soul mates, how we are all connected, and what happens after we die. It is very interesting and will change completely how you see life. At least it did for me. Both are by Michael Newton.
Journey of Souls
Destiny of Souls
And here is an interview by Michael Newton.
What makes Michael Newton so interesting is that he is the first person to have discovered the concept that our core consciousness is that of an Energy Light Being that has a life between lives in the Spirit Realm. Michael Newton spent 50 to 60 years discovering aspects of this new reality that was then written down in the two books below. This discovery was a complete accident, while trying to help people as a psychologist / hypnotherapist.
Part 1 of 5
Part 2 of 5
Part 3 of 5
Part 4 of 5
Part 5 of 5
There is a third book by Natalie Sudman who experienced a Near Death Experience in Iraq when her car was blown up by a road side bomb. Her Near Death Experience confirmed the information in the above two books. I was introduced to Natalie by Bob Olsen on After Life TV.
Book Excerpt:
At the NDERF Web site
Interview on After Life TV with Bob Olsen
James family was helped by Carol Bowman whose two young children also remembered their previous lives at a young age. Many more stories can be found here regarding children and their Past Lives.
Carol Bowman – Past Lives of Children
http://www.childpastlives.org/
Our spiritual entity is not something out of science fiction, it is now science fact.
Arnie