My in-laws are away for a month and their dog is 13.
I have lived with them for 3 months before they left so I'm not new in the dogs routine.

But recently he has been acting funny. I know he's probably fretting for them but he seems really depressed. Even my Mum who come to visit today said he looked sick.
He was at the vet the week before my in-laws left 3 weeks ago.

When we get ready to go in the pool or even pick up a pool towel he bounds around and acts like a life guard. In the last few days he's been bouncing around like this even when we havent been going near the pool or touching a towel.
He has just been moping around the house and not his usual self. I thought after his owners had been gone for 3 weeks already he would have started to get over the fretting stage.
He's also not coming when we call him for dinner, sleeping way more than he used to.

I don't know how to describe it, but he has gone funny.


Is there a chance he may be getting ready to pass away or is he just missing his owners?
Forgot to say he's a fox terrier.

Also the vet when he went said he was as healthy as can be. He has a very very low stress life.