Here are the instructions on the bottle I purchased from Global Light Network:
For Children: start with 1 drop daily, increase up to 3 drops for each 25 lbs of body weight.
So you would increase past the 3 drops daily based on his body weight only. I'm sure he will have some complications with the diahrea and nausea at first, but that is because he has so much bad stuff to be cleaned out. I wonder how he'd be if you were able to get him to "the other side" with this stuff? The other side meaning past the diahrea and nausea and totally clean. I don't know what caused his autism (heavy metals, other toxins) but I do know of people being completely cured of the "disease" through total cleansing and diet change.
You have to do what you feel comfortable with. His situation makes the cleansing more difficult..........I wish you the best of luck! :)