Try contacting Assistance Dog United Campaign. Google it! They do a voucher program for things (chow, kibble, vets, equipment) for working & currently in- service dogs. So you dont get cash but instead a voucher based on specific need of your animal. They seem to have a network of vendors & suppliers across the US that accept their vouchers (like vets) or ship the dog foodstuffs, heart meds, etc. I think a couple of the big foundations (like Doris Duke foundation, Rbt Wood Johnson) support ADUC.
As for funds, I would suggest you contact the Alzheimer's website.
Go to the upper right corner of your screen, you will see SEARCH SITE. Type in "service dogs" and search.
Good luck!