We, too, have handled this kind of thing as Bostonian's family has.  Avoid the gruesome imagery, but-- discuss.  I 
told my DD13 before she 
saw the footage (which was admittedly quite blood-soaked, IMO).
We've never tried to shield DD-- DD (2y)  was perfectly 'aware' of 9/11 and somehow managed to process that completely adequately and without emotional harm.  At that point, there seemed no point in shielding her from anything else.  Keeping information from a HG+ kid who is tuned into the world is a losing battle, IMO.
Bostonian, I am glad that you and your family are well. 
