It is heartbreaking to find your pet whether it is a dog or cat missing. It is the attachment and bond that you have built up over time with your pet which cannot be replaced. So it is sad to wake up one day and find your pet gone.
You may adopt another pet but it will never be the same as the one that has gone missing.
I can't really empathize how my friends feel but my wife and I are very very sad indeed. We knew Belle (dog's name) since she was 4 months old. She had stayed with us on numerous occasions when our friends went on vacations.
Belle was a very intelligent little toy poodle. She was a fast learner and extremely affectionate.
We hope the person who has found her will treat well if there is no intention of returning her to her rightful owners.
PS: It is a criminal offence to keep a micro chipped pet belonging to someone else. The sensible thing to do when you found a pet is to call AVA or SPCA and NOT keep it.