Well if you don't mind spoilers I can tell you the end game text about Bhelen.
During the ending it shows some flash screens of the lands you've been too and what happens to them. If you pick Bhelen as king he ends up pretty much getting rid of the caste system and trying to make the dwarf kingdom more "modern".
I don't remember what the text said in detail but Harrowmont does rule for a time but he is unable to keep the Assembly together and properly put a lid on the uprising after Bhelen's death. He still has some support for his conservative ways but eventually he falls ill and dies, supposedly due to foul play.