Is the knowledge that the brother taught and the good example he left behind after his death considered knowledge from which benefit is derived and for which he is rewarded?

The deceased benefits after death from beneficial knowledge they taught others. Its reward does not cease because that is among the matters that remain from the deceased's deeds after death. Thus, whatever your brother taught and disseminated, such as supplications, or urging kindness to parents, or other beneficial knowledge, he will find its reward after his death.