How can someone die when they get HIV then aids?

AIDS related death. If untreated, HIV slowly decimates the immune system leaving the individual susceptible to infections and cancers usually held in check by the immune system such as pneumocystis, mycobacterial diseases, lymphomas, accelerated cancers (eg: lung, cervical cancer, head and neck cancer), endemic fungal infections, and chronic wasting. All of these can be averted by haart (that means taking the meds!).