His character progressed as he was tracking Sophia. When that all went to hell, it hit him harder than most, now he's lashing out and regressing back to his old self.
His personality is being tugged in separate directions by Rick's current influence and Merl's lasting influence. If we see a return of Merl, watch the 17 out, Boondock will get really unpredictable.
He's my favorite character on the show, and he had some fantastic one liners last night. Loved when he called Lori "Olive Oil."
Speaking of Lori, the episode where she flipped the car was just awful writing. Two of the most capable members of the group went out to fetch someone that's also important. So she decided that for no reason, she wanted someone to go fetch them (pretty sure they knew to come back when their job was done), leave completely alone, while pregnant, and not tell anyone. Her character is awful.