I'd put money on having this over turned. It's a pretty long stretch to call this manslaughter based on the definition of the law (linked elsewhere in this thread).
>> Someone was killed as a result of the defendant's actions.
The victim got out of the car and only got back in because the defendant told him to.
>> The act either was inherently dangerous to others or done with reckless disregard for human life.
She may not have intended to kill him but given she knew of the poor mental state he was in, plus the fact he had just backed out of killing himself, it seems reckless to then tell him to get back into the car.
>> The defendant knew or should have known his or her conduct was a threat to the lives of others.
As above really.