Pick up "The C Programming Language", will give him a solid base to work off which is really the important part ... language is less important.
But speaking as someone who learned perl first and went back to work with C, C++, and Java later I wish someone had me learn those first before moving on to others, going the other direction tends to make people stubborn and lazy ( and i will avoid the python topic like the plague since i am not sure if people are trolling or actually believe that it is a good place to start ).