It's important to note that your pups probably shouldn't be entrusted to do what Diller does with whole avocados — but it's probably fine to let them have a slice.
"As a board-certified veterinary specialist in emergency/critical care and toxicology, I get asked if avocados are poisonous to dogs or not. Don't spread the hype — avocado is not poisonous to dogs!" Dr. Justine Lee, a consultant for the ASPCA, told The Dodo. "While it is highly poisonous to certain species (e.g., birds, sheep, etc.), the persin within the avocado fruit doesn't pose a poisoning threat to dogs."
The real threat to dogs from avocados is actually the pit. Those are a serious choking hazard and, if ingested, could become lodged in a dog's stomach or intestines. Thankfully, Diller has never had a problem handling pits, and his owner is aware of the danger.
"I would never let a dog that I didn't know was a methodical eater have a whole avocado," Moser said. "I trust Diller because I know him. He's getting to be an old man dog nowadays, and we've never had any trouble with him even thinking about eating a pit."