ADHD

Help!
I have a student who has a severe case of ADHD. He has a great deal of difficulty doing anything for a even a short period of time. He is not on any medication and his partents will not put him on medication. I do collaboration in a general ed classroom. There are many distractions and I have other students. I must always give him redirections and start him on his assignments. As soon as I begin to work with another student he is off task.