This was mostly a good read with a creative storyline but the ending lacks clarity IMO. I can see the basic idea that Alex/Sasha's fate was sealed no matter which life he led, but who is who was cloudy in the end.
Therefore I found it unsatisfying.
I went back and listened more carefully and it became more clear to me that Alex was the plane crash victim and my confusion was due to a name switch from Sasha back to Alexander in the last scene. At least that's my understanding of what happened.