It has occurred to me that we, the audience, have never met Drew. This is the first time.
BM as Drew was always just someone accepting the words of others that he was not Jason, and then changing the circle of people he interacted with (which immediately made him a better person since he was now free of CarSon.) He took the name Drew because he came to accept what he was being told as truth. But it's not something he ever actually lived. He never did not have Jason's memories. Even when he was Amnesia Jake, all of that was layered on top of what was supposed to be Jason. Even the new memories made with Kim and Oscar had Jason's past as a foundation.
So, if this was really the story, this is a totally new person to us and to everyone but Kim and the now defunct Franco (the only person to know him for a short while as a child.) Oh, and Shiloh.
I feel bad for Scott. He just lost Lee and Gail, now he also loses another child.