So we are positive the Tesla didn't have autopilot on.
Given autopilot can't make turns-and the story states the car had just specifically made a turn prior to the crash, yes, we are.
Have you never used it before?
Most likely the elderly driver made the turn, then hit the wrong pedal-- the accelerator instead of the brake- then panicked and hit it even harder. Certainly also possible he had a health related incident.
So a few things here--- first- again- this was a 2015- which means the AEB system was based on AP1, designed by Mobileye not Tesla, and not deployed on any new cars since late 2016.
Second- AEB isn't designed to prevent crashes, it's designed to reduce the severity of them-- and the manual (just like the manual of all other brands of cars with AEB) not only specifically tells you that, it lists a bunch of circumstances under which it may be unable to do even that
including if you hit the accelerator because the car has to assume the human knows better than it does.
Are you also going to the forums for all the other car brands where I linked you to a similar crash in the other thread you started on this and asking why THEIR AEB didn't prevent it too--- or just this one?