Oh boy!! That's a difficult one. It may seems like not a big deal but it is. First and foremost you have to let him/her know that (s)he has anger issues. And it is something that can dealt with some help and the person can overcome it. You have to support him/her in understanding the situation you guys are in and this anger issues are not helping.

Let her/him know that you value the relationship and (s)he is affecting it negatively without her/his knowledge...

Second one is stubbornness it's an inbuilt feature. The only good thing is it is easier to reason with a clam stubborn person than the angry one...

So focus on the anger issues.

Regards
@inuke