I own a border collie.
A Black lab? REALLY?
Meanwhile, I have 2 pits in my dog obedience training class, and they are the best students. Very attentive and smart.
My border collie had part of her ear ripped off from a Pembroke Welsh Corgi. A corgi!
It's not the dog, it's the owner. Bully breeds like pits, dobies, and rotties need consistent and firm leadership in the home. They are not dogs that can be left to lay around the house without exercise or mental stimulation.
My uncle's 6 year old purebred pit bull was born into conformation and regularly places in state shows. He will run alongside me on my bike for miles and it just a big slobberhound.
Pit bulls are predisposed to aggression, but with proper leadership, ownership, discipline, and attention, they are as loyal and well-behaved as any other breed.
My son brought home a pit bull puppy 10 years ago. He is a freaking lap dog, cuddler. 60 pounds, lets the cat boss him around. Very mellow companion.
And when not properly trained they attack mercilessly and without provocation. That elderly man had no chance and neither will your loved one if an unhappy pitbull happens her way.