Emtricitabine/tenofovir is used to treat and prevent HIV infections, and is on WHO's list of essential medicines. Literally millions of people are using it to control their HIV infections and prevent it from developing into AIDS. It can be bought on online pharmacies for $15 per month, so it's not exactly a trillion dollar drug.
It's 100% certain that HIV causes AIDS. This is uncontroversial. It's true that scientists continue to learn more about how it infects humans and causes disease. This is why treatments are so much more effective than they use to be.
There are 2 other known human disease causing retroviruses, HTLV-I and HTLV-II: https://www.health.state.mn.us/diseases/retrovirus/index.htm....
The person is quoting conspiracy theory talking points that are known, provably, untrue.