In all honestly, when someone does something like this, the last thing the parents want to hear is the idiot slobbering all over everyone expressing remorse.
IMO, just shutting up and remaining on the sidelines is about all you can do.
The guy is already the slime-ball to beat all slime-balls.
But it is something the jury might want to consider. When the only issue is the defendant's state of mind at the time of the accident, a callous silence in the face of the suffering you have caused is evidence that you had a callous disregard for life, especially if you were drunk and speeding at the time.
To deny the jury access to that information when deciding the case is to deny the parents the justice they deserve.
If you were the judge, would you have kept the undisputed FACT that the defendant did not utter a single word after killing an 8 year old from the jury?