Edit:
I am very glad your dad and family kept your cool and are all here to tell the story. Your dad deserves an award for his actions, protecting his family.
about the dogs;
I've had Dobermans, Rottwielers, mixed shepherd/dobermans, and various other mutts. I've trained dogs for protection in a formal training environment, bite on command, etc.
Breed really does not matter, except when the insurance comapany wants to jack up your rates or deny you homeowners, for having a "dangerous dog". The rotties, shepherds, retrievers and such all shed, and are a pain in the arse that way.
My recommendation for a great guard dog for the family is a Standard bred Poodle. No kidding.
They hardly lose a hair, are very intelligent and trainable. Look at the circus dogs in the first part of the century, mostly poodles. At 60 pounds or so, I would not mess with one with a smart, nasty gleam in his eye and a growl in his throat.