I think many of us have noticed at this point that the brotherly dynamic is a deadly one on this show. It can be interesting theme when used sparingly.
Rick and Shane oft described each other as brothers and started with a tightknit relationship. It was Shane's abundance of love for Rick's life that drove him mad. He turned against his own brother to almost become him -- to gain a different level of closeness. Shane was to claim Rick's wife, his son, and the unborn child that he [Shane] was convinced was his.
It was Rick's almost undying love for his brother that allowed this conflict such life. Season 2 was -- at its core -- about Rick's love for Shane, and how that prevented him from ending the past. Rick didn't have it in him destroy a relationship of his until he knew that it'd undoubtedly destroy him. Rick then went on with much regret for killing his best friend, and his animosity towards Shane's ultimate break is a driving force throughout the third season, taking Rick to extremes in dealing with Tomas.
Daryl and Merle are blood-brothers. Merle's undying love for Daryl is what finally changes him enough to take a stance against the man who essentially "saved" his physicality, and Merle sacrificed his known morality for his loved brother.
Daryl and Merle were similar to being one and the same in the beginning of the series. It isn't until T-Dog's slip up causes the group to lose Merle that Daryl finds an opportunity to earn his first true individuality. Throughout the past few seasons, we've seen Daryl flourish in the environment that Rick's group had created (with much help from Hershel)for themselves. Time-and-time again, Daryl has been presented with opportunities to revert to a Merle fashion (saving T-Dog from the traffic herd; searching for Sophia and comforting Carol; Daryl and Merle temporarily depart from the prison, but return to save Rick during a Governor attack; getting drunk with a mentally daunted Beth; holding his own against Joe and vouching for Rick, Carl and Michonne), but he stays the "better" man that he became with Merle.
After taking a thorough beating from his colleagues, Daryl is named Rick's "brother." My question is: is becoming a brother to Rick -- his official right-hand man -- a good, or a bad sign for Daryl?
Does it spell death for Daryl by Rick in a slight betrayal? Will we see a remorseless Rick sacrifice a love during a tough situation
What could Daryl's Season 5 relationship with Rick be?