But seriously...would you really like that? I mean...as tempting as it might sound...you want him to turn into a random follower that lacks personality and goes "oh look - a cave!" I'm torn on this...I don't know...
I really don`t see him bending to your will and becoming your follower. He was one of the first, if not the first dragonborn and thus I have my doubts that he would bend to your will. More like he would want you a lesser,younger Dragonborn to bend to his will, he views you as his lesser not as an equal
I wanted him to be a follower too but I can't imagine that ending well at all. It'd be another Summit of Apocrypha battle every time one of you spotted a dragon.