Sorry to hear about your friend. Hopefully he’s able to get back on his antiretrovirals.
A lot would really depend on why they diagnosed your friend with AIDS rather than an HIV infection at this point.
Sometimes a patient will be diagnosed with AIDS due to specific illnesses or even symptoms that aren’t typically present with earlier forms of HIV. If that’s the case then if their body bounces back from those symptoms or illnesses, they would no longer fit the description for AIDS, but of course would still have HIV.
With proper medication, even someone who is diagnosed with AIDS due to low T cell count can potentially have their count rise again and no longer fit the criteria for AIDS. I believe this is a rarer scenario.
As far as the virus being undetectable, that can certainly happen with the right medication, but wouldn’t necessarily improve their health directly. It would just give their body a chance to bounce back without the infection getting worse. That’s why the medications are so important and people have been able to live with HIV so much longer than before.
It’s worth noting that medicare and most states have programs with drug companies to provide HIV medication at reduced costs if someone is uninsured or can’t afford it. It’s at least worth looking into if your friend may have the same situation again once they leave the hospital. some information from a quick google search.
I hope your friend makes a full recovery, and that someone finds a cure quickly.