Ion's life sucks. Sanji knows this because from what he's been told, it sounds suspiciously like his life - only with a dash of innocence thrown in. The similarities are startling enough that the chef feels very bad for the fon master and his situation with Anise (god, and he'll flip kittens if he ever realizes Ion's dead.) If possible, he'd do all he could to relieve some of that misery, but knows very well what a tall order that is. So he'll stick for being a sympathetic ear if Ion ever needs to rant or talk to someone, despite the two not knowing each other that well.

He also thinks Ion is waaaaaaaay too kindhearted. God, kid.