Thought the fact that Darrell stepped up to put Dale out of his misery made a powerful statement that he was back in with the group.
Agreed. I also wonder if Darrell knows that Rick has a "problem" killing when he's not directly threatened. Consider it the cop in him. I wonder if Darrell was telling Rick in a roundabout way that he was okay with taking on the burden of putting Dale out of his misery. I don't recall Darrell being particularly angry with Rick for not popping Randal when his son showed up. Maybe he wants Rick to be a good example of a dad because he didn't have one.