I do not know the absolute answer to your question and I am 99% sure that no one , science or anything will be able to prove it……BUT, based on my own personal metaphysical experiences such as out of body experiences/astral projections and other non-physical experiences from the time that I was a small boy and continuing to have them ongoing presently as a matured adult, I definitely “intuit” that ALL of my Dogs, both past and present dream about those they love!
Psychologist Discovers That Dogs Dream About the Humans They Love
Have you ever wondered if dogs really dream about chasing kittens and cats? According to Harvard psychologist, Dr. Deirdre Barrett, canines are likely dreaming about their human caretakers. Barrett has been studying sleep behavior in humans for years. Although she says there’s no 100% certainty to know what animals dream about, Barrett can extrapolate what she knows about humans—because after all, we are animals, too.
One certainty is that most mammals, including dogs, have a similar sleep cycle to humans—which means they move fluidly through deep sleep to a less brain-active state and then on to stage of Rapid Eye Movement (REM). This last phase of the cycle is where dreams occur in humans. Barrett deduces in an interview with People: “That certainly makes it the best guess that other mammals are dreaming, too.”
For more and ref: https://mymodernmet.com/dogs-dream-about-humans/