need to find a way to prevent this from happening in cars? Anti-roll if no one inside at steering wheel. I am being serious, children have died in similar accidents. . Sad to learn he has died.
Why not add the same sensor to the driver’s seat as is in the front passenger seat. The one that enables the airbag. Then you just need to add an engine cutoff, or an automated brake.
One problem with "automating safety" can be that the public comes to rely on it, and doesn't understand that the technology is not perfectly reliable. Sometimes the rate of accidents actually increases as the technology "evolves."
This sort of accident is much less like in Europe, because drivers there habitually use the hand or parking brake, which is by far more reliable than "putting it in park", which is susceptible to brain farts, something we do without thinking, so automatic and done so often that sometimes we confuse thinking about the action with doing the action.
Not to say your idea isn't potentially a good one. Just saying that human nature is a huge part of safety.