Unfortunately programs that would help in this kind of situation vary A LOT by state, county, and city. Here in MN you can get help with everything from food to heat, but Georgia may be different. I'd try to contact the county social services. If nothing else they should be able to point you in the right direction. Other places that might be able to point you in the right direction: Local pastors/churches, Local branch of the AARP, city social services.
As for medicine: I think Merck and Phizer (sp?) both have programs that can provide cheap/ reduced cost for people who can't afford their medicine. Check the websites of the companies that make your grandparents' drugs to see if they have such a program and if your grandma and grandpa could qualify. Also, there are lots of websites/mail order/phone order pharmacies that import drugs from Canada. This often reduces the price by over 30%. (My dad has been doing this for my grandma for years now.) Also check the dosing of their medicine. Often a 60mg tablet is the same price as a 30mg tablet. So, if their presciption is for 30mg they can buy the 60mg, cut it in half, and get two for the price of one.
Hope this helps
Good luck!