Just a question...is finding a place to rent really the problem, or is she just looking for an excuse to surrender the dog without feeling too guilty about it? I KNOW there are a number of apartment complexes here that allow bully breeds, because I worked at the SPCA and had to call them as part of our application screening. And Raleigh's not as big an area as Atlanta. Finding a landlord may take some time, but I can't believe it's just not possible. But I also know many people unfortunately use moving as an excuse to surrender their animals.
If it really is a landlord issue, you could use something like apartmentguide.com, search for complexes that allow pets, and then just start calling. Or you could search the paper's classifieds online for individual apartments for rent. In my experience, landlords with one or two properties are often somewhat flexible in their requirements, and may prefer a well-mannered adult dog to a very young puppy with chewing and housetraining issues.
If she's set on giving up the dog, there may be a limit to what you can do to change that, but I hope for his sake that that's not the case. I agree placing an eight year old male pit bull with heartworms would be really difficult, not to mention how traumatic it is for a dog to be given up after that long. So sad...I really hope you can help her.