TBi
macrumors 68030
If you fixed her computer why doesn't she return the new one she bought and just use the old one again instead of you ripping her off whoever much a new MBP costs?
She gave him a dead-to-her laptop. His fixing it does not mean he has to return it as she gave it to him broken and useless to her.
He got lucky and it was an easy fix but by the same token she could have easily fixed it by playing around with it a little bit more.
If she returned her new laptop to take the old one back he would be fully within his right to charge a 'repair' cost of the 900 as quoted by apple. No prices were quoted so he can say whatever he wants.
Whether or not it's the decent thing to do or not, he is legally in the clear.
To the OP: Lucky fecker