It is true that some Suzuki students have trouble with reading music fluently. In my experience, good teachers do not let this happen - this is why it's important to get a reliable, recommended teacher, not just a 'Suzuki' trained one.
Have a look at It won't help with HK teachers, but it will give you an idea of the training methods and principles.
At the end of the day, you want a child who enjoys practicing, and making music. Especially for school children, ensemble playing can be a real source of stimuation and enjoyment, and it's a shame if a child has great musical abilities, but not the reading skills to get the most out of it. I'm not discouraging you from using the Suzuki method, but I think finding a good, patient teacher, is more important than the 'method' - especially of you child is a beginner/quite young.