“I think they want some accountability”
“And what is wrong with them wanting her to answer for killing their son?”
“Was it an accident? Or was it negligence which resulted in the death of the motorcyclist”
I agree. If subjecting her to punishment in England is the issue, then punish her here. At the very least, she should be fined, and the money sent to the town or city where it occurred, given community service, and pay some sort of restitution to the family along with an apology.
She didn't break the law here. Our courts have no jurisdiction over British traffic offenses.
As the wife of someone with diplomatic immunity, the U.S government should probably provide restitution to the family.