Get some Styrofoam sheets and cut them the size of our shipping box. I would go two sheets thick all the way around the steaks. Pack all the steaks in and fill any voids with either packing peanuts or newspaper or whatever insulating material available. Then check who you plan to ship with and see if they allow dry ice, if so use it. Ship out overnight first thing in the morning with the streak completely frozen with fresh dry ice on top. Depending on the weight, it will run you $100+ to ship something overnight + perishable, but if its for your dad its worth it I'd say.
I send a friend a care package back in December of duck breasts, elk steaks, jerky, sausage, etc. and used the Styrofoam sheet method along with the insulation sheets that came with one of those complete meal packages for the voids along with three ice packs. He received the package the next day and the ice packs were still half way frozen along with all the meat still frozen. It ran me $120