He did overstate it, but malaria provides more negative pressure on reaching breeding age than sickle cell.
Biology doesn't care about people reaching into old age, just giving them the best opportunity to reproduce and raise young.
This results in sickle cell being more prevalent in malarial areas than clear areas. It is why blacks have more sickle cell than other races, even when out of danger for hundreds of years.
Which is why Huntington's corea isn't particularly selected against, nor is Alzheimer's.
I consider the general a friendly opponent. And as I said, I am from Missouri, show me. The 14 month period of advantage(although the way I read the graph it carries on into about 24 months) for the HbAS carrier is to be compared to the disadvantages of the trait carried to around 10 years or 120 months. That period is much longer before reproductive capability.