now this person doesn’t have the drastically higher chances of surviving Malaria

Do they not?

one parent passes on the gene it doesn’t lead to sickle cell yet it provides the benefits against malaria

They can’t have edited all of the patient’s cells, just enough of them to produce enough normal non-sickle blood cells to cure the disease. Would the remaining cells which still prosess the sickle-cell gene provide any protection against Malaria?