It is a language problem based on words. The three appellations * * * have appeared several times together. This question can't be answered numerically, but in the era of grandpa, dad and son, a * * * is three people.

Immediate family members include immediate blood relatives, spouses, collateral blood relatives within three generations, grandparents to parents and then children. This is three generations, including their parents and their children's relatives from top to bottom.