He may be immune now....who knows?
This is the Delta-32 mutation, and it also giver the person immunity to the black death.
I think HIV is a retrovirus. If so, a person could have every single one of the viruses in their body be gone and still be infected.
Retroviruses are sneaky suckers. They “splice” their own DNA into your own personal cellular DNA. Then they may or may not croak.
At some point in time, for whatever reason, sometimes your own cells start copying the new DNA and they (re)produce NEW COPIES OF THE VIRUS.
So now all the sudden, you are re-infected.