My father, an elder and sometimes PO, was so strongly against nepotism. To the point where he took extra strides to prove he wasn't. Perhaps the reason he was against it is because he saw it happen on the elder body.
But when I was growing up, I just wanted him to be more a father first, an elder last, rather than the other way around. Give me some favor of some sort!
Maybe I'm going out on a limb, but I think some of this nepotism may stem from "natural affection" and wanting to protect ones children from harm. An elder who is willing to see their child disfelowshipped and shunned is just not that good of a human being.