How can you help someone with an over active mind?

My husband for over five years has had an over active mind. Thoughts are rolling around in his head like a movie reel and it is driving me nuts. He even talks in his sleep , when he truly sleeps that is. He is always moving , never still. He can not focus on any one particular thing for any given amount of time and ends up making huge mistakes. What can i do to help this , he is denial that there is a issue but there is and unless i get him some help in some form , he is going to have a nervous breakdown. That is dangerous when he drives also.When i go places with him which is rarely anywhere lately, he drives fast. But our daughter loves to go with him and i am afraid of his overdrived mind that someday he may forget she is in the care with him and drive too fast and get in a wreck and hurt her.