From Rex's Mom:

Colonel Rex passed away during the night between Thursday and Friday. He had some food on Thursday morning so I decided we would try to get one more nice day out of life for him. He managed to accompany us on two walks. Towards the evening he was lying outside in the backyard; he came inside the house for a brief time. I could see he was not faring too well but I was hopeful he'd make it to the next day. Well, unfortunately, things went downhill very fast. He decided he wanted to stay out in the backyard all night, probably because he knew it was the end, and didn't want to upset me. God knows. He left this life without making a noise just as he had entered it and likely like he always was. I was very upset not to be able to do things as I had envisioned them: get him a proper, dignified ending without pain; I reckon I waited too long. We buried him in our dogs' cemetery, and there he will rest in peace. As with every time we lose a dog, everyone in the family feels very down and upset. The only consolation we have is that we managed to give him an extra 10 months of good life and a forever home - in case he wants to come back. ;)

Here's the funniest picture with Rex: I gave him a large container of yogurt to lick, and when he finished it, some yogurt remained on the top of his nose. ;)