Just to make you feel a little better I'll let you know about my own dogs' grief.
My brother and sister in law were getting a bit too crumbly to look after their two yorkies. It had been my brother in laws intent to breed Yorkies for a profit. The mother Gem, a granddaughter of a Crufts champion, had a litter consisting entirely of bitches. He was so upset by the types turning up to buy the puppies because it was obvious to him that they had every intent of using them as brood animals on puppy farms that he found good homes for all but one (Tip) who was kept.
We went down to stay with them a couple of days and took the dogs back home with us. The first night they howled. We thought they were missing their owners but as soon as we opened the bedroom door they were in and and on the bed quick as a wink. That's all they wanted. Several years later we went back to stay with my inlaws again and wondered if the dogs would make a fuss of them. Nope they didn't bat an eye and came away with us when we left without even turning round to look at their old home and owners.
When the mother died we expected some reaction from her daughter. None at all - you'd never know that her mother and constant companion of 15 or 16 years had gone.
In my experience dogs have zero sentimentality and not even a jot of loyalty so long as new owners treat them well.
Oh I forgot to mention - in the years we had those two and all the years we had dogs previously not one of them ever spoke to us. If you think yours do then a bit of professional attention is the order of the day and not for the dogs.