I thought it was sad, but it worked. Worf tried to give his brother an honorable death, but Starfleet stopped him. After that, his brother was in agony and Worf loved him too much to let him suffer for his sake. He had no idea when he might get his honor back or if he'd keep it while walking the line between 2 cultures. If there were a battle he could have sent his brother to die in, then I think he would have done that, but as it were, he did the best thing he could do. That's what makes it so tragic. I think that we don't see him mention his brother when he gets his honor back because who would he say something like that to? He wouldn't, not even to Jadzia unless it was very quietly in the middle of the night at some point. I think he carries a lot inside of him and he's used to not sharing much. Klingon warriors aren't prone to spilling their feelings much anyway. FWIW, I liked his brother as a character too.