Factual error: John Grady Cole's father says that the last time he spoke with Cole's mother was in San Diego in 1942. His lighter has a 3rd Infantry Division badge which means he fought in the European theater of WW2, not the Pacific Theater.
Factual error: During the multiple hospital scenes, the doctors direct their updates to Will, ignoring the closest family member, her grandmother. Will's relationship with Charlotte is not even a year old. No hospitals or doctors would ever discuss this condition with anyone outside the immediate family, including and especially the Cleveland Clinic.