I have a 2yr old boy with cerebral palsy and I was wondering if it is safe to place kyanite on him as I have heard that kyanite helps the cerebellum and motor function of muscles. I purchased a kyanite pendant that I have been wearing myself, actually wore non-stop for a week and my son took his first steps walking unaided. Not sure if it was a coincidence or not.

You know, I'm getting you might want to learn how to muscle test.  You can test for him.
It's not hard, there are several ways.  I would imagine there are many things you are going to want to try with/for him. At any given time, you may want to test him to make sure he is open to the energy you are wanting to give him.
Muscle testing is a good way to tell.

Reflexology.  I also got you may want to check into reflexology.  
That didn't answer your question.
I didn't get a specific answer, just to be sure and learn how to muscle test. When you learn, be sure and ask the person who teaches you that you want to test for someone else.
Also, I know it is sometimes hard to find teachers for these things.  If you are really wanting/meant to learn it, ask, the teacher will arrive.

There is good into on the net for both.
I am seeing you testing, muscle test, to see if it is a good time to put a crystal/stone on your son for a while.
I am seeing you apply it to the corresponding place on his feet to send the energy directly to where you get that it needs to go.  
The muscle testing will help.  It can give you amount of time to apply the stone and what part of the foot,   I would imagine a pendulum will help.
I am getting this as I type.  It is not something I have specifically tried.  I have done similar things.  Because he is a child you want to test and always you want to do this with the intention that the highest energy appropriate for him be used and that the highest purpose be served.  
I am channeling.  Please check this with your own guidance.

Thanks for your advice Tourbi, it is much appreciated and I will look into it.

My friend, I get that you and your son will do wonderful things for him.  It is a joint gift you give each other.
It is all based on love.  From the love, there is little you can do that is wrong.
I am happy to pass on the info I get.  
I still am hearing loudly, that with the skills learned mentioned above, you will always be able to test and do what is appropriate at the time.  I get rose quartz will serve him well.

Also, some grounding stones.  Also a stone for balance.  I use a trampline, a small one, It helps me with balance.  
In my reading about them I discovered that they are now used for kids with learning disabilities.  Many kids with "chemical imbalances" and learning disabilities are not using both hemispheres of their bodies.  After bouncing everyday for a while, the kids do better in school and do better physically also.
I am getting you can put him on a rebounder and then gently bounce him. He will probably like it and it may help his brain.  CHECK it out with his Dr. first.

I'm happy that I got info for you.
I get that you two are going to have a grand life together as father and son and as friends.
Enjoy each moment.  Each is a wonderful gift.