Do 4 years old children NEED to go to school?

I am so confused. Here I am in Malaysia where most children start going to kindergarten at 5 years old. Yet where I came from (Singapore), most children start learning as early as 2 years old. I sent my son when he was 3 to a nursery last year. But this year due to financial instability and extreme time constraint, i decided to put his learning to a temporary halt. This however has caused a uneasiness for my mother as she's scared that her grandchild will not have good education. I feel so helpless and useless.