Hi Celeste,
At what age the child is unable to instantly recognize quantities seems to depend upon the child. For example, Domanmom (a mom on this forum) started her son when he was 30 months. He was still able to go through the program and learn to do instant math. (
http://forum.brillkids.com/teaching-your-child-math/anyone-get-results-from-doman-math-method/ ) But I did read that it is good to teach numerals and switch to numerals before they lose the ability to see quantities. (They say it is usually around 36 months, but I'm supposing that is an average and some lose it sooner and some later.) I suppose your friend could start the math program and see, if she wants to. Even if she only makes it to 20 dots, she will be able to teach many of the math concepts using those. I would also suggest having the numbers in a grid rather than random, as older children have an eaiser time that way.
But for reading and EK, I think there would be no problem at all.
P.S. For how to teach math, this link was helpful.
http://forum.brillkids.com/teaching-your-child-math/maths-equations/15/