I think I didnt read all of your opening post, are you saying that the truck went into a Cranking mode and since it was in gear at the time, the starter powered the truck and rammed it into the tree, after which the windings in the starter got hot enough to melt the insulation off of the main hot wire to the starter, and thus creating a fire that consumed the front of the truck, right?
Wow, that is crazy!!!!! I am glad no one got hurt!! That would have really sucked if it ran into a Lexus or something and then caught both of them on fire 
Sorry about my misunderstanding, I sometimes do that 
So does your home owners or something cover the loss? 
No it caught fire which shorted out the starter, sending it into cranking mode and up the hill. Fire happened BEFORE it started and moved itself
But yes our angels were workin over time, it did melt the lenses on one of the cars though, the side marker and front turn signal/parking lights
and bubbled the paint... mom guesses bout $2500 worth of damage on a new car like that
