The biggest contribution from the massive levels of research on AIDS is not curing the disease. That will be wonderful when, and if, it happens. The biggest contribution will be that, as a result of trying to cure AIDS, we have learned immense, really truly immense, amounts about the immune system and it's incredible intricacies.
And, guess what? Ultimately, it is the immune system that keeps your body free of cancer. Cancers happen frequently in your body, and the immune system beats them down. When it fails at that for some reason, only then does clinical disease happen. I've heard it said that most people have 6 or so small cancers in their bodies at any given time, all being properly managed by the immune system.
Understanding the immune system, because we have been trying to cure a disease of the immune system, will eventually do more good for human health than any other single effort since the invention of antibiotics, with the possible exception of magnetic resonance imaging.
But let's look at the GP's assertion about money. The National Cancer Institute's budget appropriation for FY15 was $4.9B. They're the part of the NIH that sponsors cancer research. The National Institute of Allergy and Infections Diseases, the NIH that is charged with fighting AIDS, had $4.3B appropriated for FY15. Even if we assumed that the entire NIAID budget went to AIDS (and it does not), the NCI has a bigger budget. So the GP is just flat out wrong with his initial assertion: much less research effort in the form of NIH extramural support is spent on AIDS than on cancer.