If you’ve had it and recovered, you have the antibodies and are immune. What he is talking about is a wave of infections, a period of social distancing where the number of cases retract, and another wave as people begin to act normally. But I think that the virus has already infected enough people with mild to little symptoms that new cases will become rare as the number of non-infected people become fewer.
I think he would understand that if he studied microbiology. I tend to think you’re right even though I have no expertise in this area, because the same flu strain doesn’t keep returning.