They were going to get ice cream when the crash happenned so I don't think they were running away from him, although that could be revealed in time.
I can't remember who was driving the car.
He never said who killed his brother, just that he was killed in prison and the band was the name of his brother's band.
In the latest episode he starts seeing his wife and daughter and is at the grave at the end and says he is going to make Mike pay (or similar) so it is definitely Mike he is back for.
I just find it hard to believe it would be so obvious and think there must be more to it, I hope so at least as I'll find it disappointing otherwise even though I'm loving this series