I have seen this EXACT behavior from an older gentleman I know. His health is, um... fragile. He had brain surgery a few years before I met him and his behavior was just as erratic and randomly bizarre as Joe's. Recently this person had to go into the ER for some pneumonia and now he carries an oxygen bottle around with him. To say he is mentally challenged now is a kind understatement. He cannot maintain a stream of thought, and conversations with him are very confusing. He remembers things from the past but cannot seem to adequately articulate what he wants to say.

Every time I see Joe in public, he reminds me of this guy I know. Not functioning at even 50% capacity.