I think this both a happy and sad story. Happy in that they, obviously, complement each other. Sad in that, no one else was prepared to show them the life long kindness necessary to get though this condition and the only person who could was themselves handicapped. I think the handicapped pairing up with the handicapped is a damning indictment of society and how society "victimises" the handicapped.
People should treat others the way they expect to be treated themselves.