1996 Chevrolet Tahoe electrical system problems

My 3 year old nephew was able to get into his parents 1996 chevy tahoe and was able to turn the key to the first click (before the click to turn on the radio and power windows, etc.). Then without touching the brake, the toddler was able to pull the shifter into neutral and the vehicle was able to move. The toddler either was thrown from the vehicle or was scared and jumped and was run over by the vehicle and killed.

The wiring harness that conects to the turn signal modual, the wires become brittle and are breaking. The first wire to cause me a problem was the wire for the headlights, the headlights would flicker on and off untill the wire finaly broke and then there were no lights at all. The next wire that broke is the wire for the cruise control broke. And now there is no cruise control. The headlights I was able to reroute the wire and reconect to the light switch to powerup the relay with the switch.