Agreed. Could be as simple as corroded battery connections, or as complex as a computer module malfunction. You should take it to a shop/dealer to have it diagnosed.
Not necessary unless you get a check engine light telling you there is a problem. Then, this would be the first thing to try before replacing it. Unless you just like to take things apart and clean them.
So he was doing that kind of speed with family and kids in the car? I will not go any further except to say that was a very stupid thing to do. You go ahead and make light of it. All I can do is SMH at the ignorance.