I visited my friend the other day, and I noticed that his dog has stopped noticing his and my presence. What you said about how lethargy and lack of appetite are signs of a pet in pain is very worrying. Hopefully, this article can convince him to take his dog to a veterinarian specialist for diagnosis.
Thanks for pointing out that a dog in pain would ignore food and become lethargic despite being an active dog. I like your suggestion of reaching out to a vet so that they'd get taken care of. I'll be sure to suggest this to my friend who became a dog mom recently.