Sometimes relatives open up more about relatives after another member of the family dies. For one reason or another they may feel more comfortable telling certain stories when a certain member of the family is no longer living. These stories may about the deceased relative directly or about certain close relatives of the recently deceased family member.
Consider (if possible) re-interviewing relatives after another close family member dies. It’s not just “family secrets” that may come to life. Sometimes the fact that someone died causes living relatives to remember things they could not remember before–even details that are of an innocent nature.