That is a nice blade, and a nice scabbard. I have no real advice on repairing the horn other than epoxy or super-glue. As for fixing the blade back in the hilt, it will have been glued in with a resin compound.... So do a search for cutlers resin or cutlers cement. When making it up use a glue pot (double boiler type) or melt the ingredients in the oven at a set temperature. I made the mistake of trying to do it on the hotplate and burned the mixture.
