02/22/2010 at 04:19 PM EST
unique understanding of dogs earned him the name the Dog Whisperer, but he didn't work alone. He had a secret weapon, a capable assistant and constant sidekick in the form of 16-year-old pit bull Daddy
, who died last week after spending nearly his entire life with Millan and his family, according to Cesar's Way magazine
Daddy came into Millan's life when he was just a 4-month-old puppy. Too challenging for his original owner, rapper Redman, Daddy was folded into Millan's family, and eventually became an example of a calm, submissive pit bull that was always around to help Millan in a training pinch
The chestnut-coated pup was often photographed smiling, rolling around on his back, or cuddling with other dogs, both large and small. Sensitive to emotion, Daddy would try to comfort humans or dogs that were feeling sad or upset.
At 14, Daddy was nearing the end of his life, and Millan decided to retire him. Luckily, Daddy helped nurture a protégé in the form of gray pit bull Junior. His post-retirement life included a successful battle with cancer, thanks to the help of chemotherapy, but on Feb. 19, Daddy said goodbye to his pack, and to his own daddy, Cesar Millan.
To honor Daddy's memory, Millan's foundation has set up Daddy's Emergency Animal Rescue Fund
, from which assistance will go to dogs that are victims of violence, abuse or disaster. Leave your condolences in the comments below. And click here to see a photo gallery of Millan's beloved pooch on PEOPLEPets.com.