The goal is to provide him with the best combination of length and weight that he can comfortably swing and control, while trying to maximize the performance of the clubs. True, a short person does not always need short clubs, but as with every person, you have to evaluate the impact patterns when testing different length and weight clubs. Ideally you want to fit him into the longest lengths he can control and hit consistently for his ability.
One thing to be careful of, is a short person doesnt necessarily need short clubs, and vica versa. Its also important to consider arm length. For example a tall person whose wingspan ( measure both arms extended) is longer than his height, will need shorter clubs than a guy with same height but short arms.
I used to play golf with a little 8yo kid, he was competent playing with standard length clubs. I recalll his driver reached his nose.