People train dogs to be a service dog for special needs people. I would suggest a golden retriever or a labrador retriever. They are both great dogs! Good luck!! also, I wouldn't suggest a high energy breed with your children...golden retrievers and labrador retrievers are pretty mellow imo.

one more thing, I don't know where you live, but here is a site that has information about service dogs..

http://www.k94life.org

again, good luck on your search!