i think i've said it here or maybe somewhere else, but conflict between daryl and mearle is unavoidable at this point. my bet is daryl chooses the group, and is forced to kill his brother to protect them.
True, this is confrontation just waiting to happen and I can't wait.

I can't imagine Darryl siding with his brother on anything.
Remember (last season I think) when Darryl was stranded by the creek/river, unconscious(and walkers around.) It was then Darryl was imagining hearing his brother's voice, putting him down and trashing him, that gave him the inspiration to survive. Yet, gotta say, a character like Merle sure adds to the plot. I just don't expect him to last thru this season.
TIS