My dog is 14 years old and for the last 10 months I can not leave him at home. He will bark the entire time?

will bark the entire time that I am gone. I live in a duplex. I have to take him everywhere. When I go into a store he barks constantly. When I pull up to McDonalds or Wendys he barks and cries. This behavior is out of hand. He constantly has to have me within eyesight. I am disabled could I get a permit from my doctor for him to go places with me that he is not allowed?