Both jumper cables attached to positive post

What is your question?

I am trying to help my buddy who says his friend helped him Jumpstart his Mercedes with the positive jump start post under the hood and this genius attached both cables to the positive jump start post and tried to jump start the car like that!! No lights or anything. I am going to go look at it this weekend, my thought is it is the computer? Any thought? Main relay, or fuses or what? And do you need to have the dealer reprogram/flash the ecu if it is replaced?