No it wont, unless the alt is on its way out anyway, its the say and getting a jump start, battery is dead, you put in just enough juice to start your engine and then the alt takes over.
If he is worried about it he can always charge the new battery before installing it.

He does need to make sure the battery cables do not touch anything though, if they ground out that will fry something, I take the gloves out of the back and put the battery cable ends inside of them to keep them from shorting out.

 

"I've even seen a special 9 volt battery thing you could plug into the cigarette lighter" yup it works, BMW used to sell a special tool to hold the computer memory, it turned out to be a cigerette plug with a 9 vt battery in it.