He’s usually high. So not focused imo.
I think he is.
I enjoyed the segment in the last week's episode where they were looking at their neighbor (I forget her name), discussing her "infection", and Nick said thoughtfully, "They're not sick, they're dead."
"Nick, how can you say that!?"
He just looked at them like they were crazy. "Because it's true."
So, yeah...he has a certain grip on the situation, despite his addiction.