Their two dogs are large enough in size but are way up in years so they have been considering what breed for the replacement. I've advised them first to stay with the two old dogs when outside and at night as they cannot protect themselves any longer. Next, I've advised to go with a larger breed than the small breeds they are considering for the new ones.
Small dogs and cats are both at high risk from coyotes and fox.
I’m from Texas and can tell you 2 coyotes and can sound like 20.
German shepards usually do well because of their protective instincts. At least that is what my father has found, with his two always vigilant against human and animal intruders but well-mannered with approved visitors.