I'm understood that GR (Ghostring) works against monster's Spiral Pierce and Earthquake by reducing their neutral property, anything else, DOES NOT work in PVM.
Also, HPs must be curing / blessing stoned/status'd players because at some point Beelz likes to spam statuses. It is good to have a second tank too, just in case Beelz Expulses the main tank (teleports it away) and breaks free, but its not really neccesary (1% chance).