From what I have heard, Jenner was NOT speeding but rather driving too fast for the conditions. Jenner was also not the original accident but a subsequent accident (chain reaction). Further, Jenner’s crash pushed the car forward and then another car caused the fatal crash.
Any prosecution for manslaughter will be difficult at best.
Surprise, surprise law boy, if you rear end some body; IT IS YOUR FAULT PERIOD.
Learned that the hard way.