Insurance companies in many countries do not offer a policy to someone if they are HIV+ or, if they do, they might not cover HIV-related medical expenses.
We have partnered with an insurer that can provide travel insurance to residents of almost any country, travelling to almost any country. It can include pre-existing medical conditions and it might be possible to insure them without even going through a medical screening process. You will be able to read the questions when you reach that part of the quote process.
You can buy a policy for only one trip, a long-stay trip or an annual, multi-trip policy.