In my experience as a nurse - HIV infection can exist for a very long time without progressing to full blown AIDS. Someone can test HIV+ and be asymtomatic. It is only when one of the AIDS defining secondary diagnosis occur will the patient change status from HIV+ to 'having' AIDS. Karposi's Sarcoma is one of those diagnoses. As is PCP - a rare form of pnuemonia.
I have had patients live with HIV and even AIDS as a chronic illness. In fact, when I was kidney transplant coordinator - we did kidney transplants on HIV+ patients if their CD4 count was low enough. They were far more likely to die of their renal disease than AIDS.
As a nurse, I was tested annually (my choice) for HIV and all the Hepatitis' because I was exposed to all the body fluids of all my patients. Especially in the OR. Not everyone knew they had HIV and we were trained to assume every patient did.
I'm so sorry for the loss of your friend. It's incredibly difficult to find that kind of love in the world. <3