Why does it mention Chachamim dying?
Rashi: They are not saved from death - therefore he does not toil to redeem his brother.
Radak: Since they die, how will he (the Ashir) be saved?!
Why does it mention Misah regarding Chachamim, and Aveidah regarding fools and crude people?
Rashi: It says Misah about Chachamim, for only their bodies die in this world. Radak, Malbim - their Neshamos and hope do not die. Fools, who pursue and love this world, they and their Neshamos perish; they have no hope after death - "v'Tikvas Resha'im Toved" (Mishlei 10:28).
What is "Cheilam"?
Rashi: It is their money. Radak - their wealth, which they engaged in this world, they leave it to others, and it does not help them. Chachmah that Chachamim engaged in, it helps them after death. Malbim - regarding money, there is no difference; all leave their money to others (heirs).