First of all, listening to the music to be learned is the key pedagogical principle in the Suzuki Method, auditory learning happened only after the ability to play the music was developed. By hearing the recording before learning a piece, students internalize an overall concept of the music. The process of absorbing the entire piece through the ears supports what educators call "whole to part" learning. In other words, you need to give him to listen to the suzuki's cd daily in order to make memorizing and performing easier and more secure.
Secondly, Repitition. Children listen to the recordings of their music over and over again and play their assignments many times. They need to practice every day so the parent and teacher should provide opportunity and incentive for as many repetitions as the child needs.
If you want to go more details for the suzuki method, you should buy some books for the head start.
I would highly recommend "Studying suzuki piano" or Nurtured by Love, It is a must for either parent or teacher if they want to teach their child in suzuki.
You could get them from amazon.com
or go to
http://mmg.theygsgroup.com/ which is a good site for further teaching a little child in reading music notes and theory in fun and easy way.
I started to teach my child when he was three and he has been playing Twinkle variations for couple months since this piece is the most difficult one in the Vol 1, Unlike the the traditional teaching, once you manage the techniques, you will feel great when you play the rest of the pieces and your child will become more confident and more motivated then, That is the intention of the suzuki method. Now I teach my son scales, what impressed me is he can play it very legato and beautiful.