You never want to send the child with ADD and Auditory Processing issues out to do an important task unless you have made absolutely SURE that he listened to ALL of the instructions. And maybe even repeated them back to you. Just to be on the safe side. It also helps if the child wasn't already engrossed in something at the moment. If he was planning a battle with his plastic soldiers, you may as well forget it. Do the job yourself.
Because when you say "Go in the backyard and turn off the water to the pool," that child will not hear all of what you said. He will either hear the part about going into the backyard OR he will hear the part that has something to do with water OR he might hear the word "pool". If he hears "backyard" he will probably go feed the dog. If he hears "pool" then he'll put on his bathing suit. If he hears "water" he will already be thinking of all the possible things concerning water that you may want him to do. So that he can run out and do it as fast as possible and get back to whatever he was doing before you bothered him.
And then you'll look out the window two hours later and realize that your pool has flooded and your backyard is standing in water. Because the boy turned OFF the water to the garden that wasn't on to begin with.