User blog comment:Matt585/Greek myths from the POV of Percy Jackson/@comment-4649443-20130606011754/@comment-4649443-20130610033520

And also, "Castor died, so Pollux shared his immortality with Castor, so that they would switch between who stays in the underworld, and who stays in the living world. Our Pollux hasn't done that...."

Also, he may compare the Clarisse/Silena friendship to the Achilles/Patroclus friendship(my brother found similarities).