BB has great advertising, that is not the same thing as being a great food. There have been a lot of people having vomitting and diarrhea issues with BB lately.
I think you are right about the protein versus carbs thing. Seniors have less ability to absorb the protein in their diet and can need as much as 50% more, not less. There are specific medical problems that may need the protein reduced, but your vet would be talking to you about diets specific to kidney or liver disease if that was a factor.
You may just need a good ALS food with a joint supplement added. No food has enough joint supplementation to actually have a therapeutic dose.
Maybe look at NutriSource.
