I just got a new kitten and he is terrified of me. Every time I get too close he runs away, yet he is CONSTANTLY playing with and folowing around my two year old male cat.
Some kittens are simply shy and need time to grow accustomed to new people and places. You need to be patient and let him get to know you at his own pace. Get down on his level, i.e., sit or lie on the floor, talk or read to him softly, coax him with treats or toys. It might take a couple of days or weeks, but he'll come round, especially after observing how your 2-year-old interacts with you.