Why exactly are things between Dirk and Dave so awkward currently? Is it their personalities, the situation or...?

This is tough to explain.  Dave has mixed feelings towards his Bro after reflecting on all the abuse and hypermasculine life style he made Dave lead which he explained a couple weeks ago. Dirk is just awful at talking to people in person, plus it was only a few hours ago that he realized how shitty he’d been towards Jake in their relationship.  Basically both parties are insecure and not sure how to approach one another.

This is a really bad character analysis. Dave and Dirk are not characters that I can go on and on in detail about their mindsets and the reasons they do things. So I apologies for that.