The conflict between brothers is a recurring theme in the Torah. It starts with Kayin and Havel, continues with Yitzchak and Yishmael, re-emerges with Yaakov and Esav, and now comes to a climax with Yosef and his brothers.
Yosef is his father's favorite, as indeed was Esav, but this time we know that the favorite is designated for greatness because of the dreams he gets. His father must surely have realized how much Yosef was hated by his brothers, because he knew that Yosef was talking to everyone about his dreams.
So why did he send him off alone, a long way away from home to them? Surely he might have guessed that he was putting him in an invidious position, that something might happen. Or did he, as most parents do, fail to recognize what he would rather not have seen? In other words, is the conflict between brothers something built into them? Is it their fault? Or could you say that it was the fault of the parents?
In the case of Kayin and Havel, there is no textual basis for suggesting that Adam and Chava contributed. But in the case of Esav and Yaakov there certainly was. The Torah says that Yitzchak favored Esav whereas Rivkah preferred Yaakov. And in the case of Yosef it is clear that the colored coat was a sign of favoritism.
Was this favoritism blind in Yitzchak's case? It seems so, both literally and figuratively. But what of Yaakov? The Torah says that his reaction to the dreams of Yosef was to "mark" the situation. Perhaps he felt that Yosef had a special mission and was merely carrying out a Divine plan--in which case he might have felt that God would protect him.
There is another issue however. If it is clear that one child is indeed suited to a specific role, shouldn’t a parent encourage him or her, even if it means showing some favoritism (so long as this favoritism is balanced by showing love for the other children in equal measure)?