Older dog dropping weight

A friend of mine has a 14 year old lab x collie and they are having trouble keeping weight on him. He is otherwise in good health and enjoys his gentle walks everyday and eats well. They have given him more food and followed the vets advise about giving him extras as well, he loves his piece of hot buttered toast of a morning

Despite this he is still losing weight and also beginning to lose muscle tone. The vet says its just down to old age and to try and keep feeding him up. He cant have pork and doesnt like wet food but anyone got any ideas on what they can give him to help?

Older dogs often can lose weight and muscle, especially around their hindquarters. I think the metabolism changes as a dog ages. There may also be stiffness and joint problems. My old flatcoat lost weight - quite noticeably from his back end. He became arthritic when he got old and even though he ate quite well, he did become thinner, although his chest and forefront remained strong and well built which helped him compensate.
Fresh stuff and extras alongside normal food - little and often, I think, maybe a good option. A bit of extra fat (like the buttered toast) is also good. As long as he has good quality food and keep up his exercise as long as he wants to go, then I am sure your friend will be doing the right thing for him.