Manny at a visit with Dr. Esrick [PHOTO: SAM OGDEN/DANA FARBER]Emmanuel “Manny” Johnson, Jr., shares many loves with his little brother, Aiden — from basketball to video games. One thing he wishes they did not share is sickle cell disease (SCD), so Manny is playing a role in a new effort to improve treatment for patients like 7-year-old Aiden, himself and others living with the inherited blood disorder. …