Considering he's fought his own version of Izo and has had to listen to him scream about his own despair and grief, I think Hizen would be like, "Oh, this again." Add in the fact he's also inherited Izo's story and understands where it's all coming from he might open up and say some things to Izo he'd never really say otherwise? Anything to help his precious master even if it means having to.......... speak from the heart............. u_u