I have a 14 year old finicky eater myself. For most of her life she ate dry kibble (Wysong) and would eat well enough to maintain her weight, but always seemed to "hold out" for something better to appear in her dish. This year she developed kidney disease and I can no longer allow her to regulate her own feeding, so I now prepare fresh people food for her.
It has turned out to not be that difficult and certainly worth the extra effort to me. I am not a chef nor do I eat meat so I did have to ask a lot of basic questions to friends. My vet gave me a special recipe for kidney (low protein, low phosphorous) but there are recipes all over the internet and here at pet talk. Unless there is a condition you find out about that requires a special diet, I bet adding some ground beef or chicken to your dog's dish would be too enticing to pass up. You mentioned the dog is use to people food, I'm willing to bet the best kibble in the world does not compare in taste. Of course I agree that table scraps are not a good idea but plain meat, certain vegetables, and plain rice are good for dogs (the kibble is made from something after all!). Maybe some of what you prepare for yourself can be left aside and left plain for the dog?
Mixing kibble with broth, as previously mentioned, is a good idea (didn't work with my dog). Mixing kibble with whatever food works makes preparation easier for you and tastier for the dog. Cottage cheese is good for doggy digestion and Sadie loved it (it's high in phosphorous and now off the list for her). Raw or hard boiled eggs are great for the coat (your preference on which preparation you think is healthier). There are lists online of what foods to avoid because some fruits and vegetables are not for dogs! Sorry I don't have any links.
Dogs do get more finicky as they get older so hopefully nothing is actually wrong with the dog. I agree that a vet check asap is best, but I also think it is healthy to question the vet, do your own research, and seek second opinions as you feel necessary. It works best if you find a vet you feel you can work comfortably with since you both have the same goal!
Celtic Dreamer - have you tried pills in cream cheese? How about the manual method of open snout and place on tongue? Fortunately my Sadie seems to like the cream cheese but she does sometimes need help getting it into her mouthbut after that she actually swallows it herself cause deep down she knows she actually likes it. (Sadie is on 7 vitamins and supplements a day so this is quite a familiar routine!)
Best of luck to all of us with senior dogs, and thank you Farmgirl for taking in one already in his senior years. PS Sadie says 10 yrs is a youngster.
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