Who is who's mom, who is who's dad

After 80, a girl can marry a 40-year-old man. If a man is qualified after the 80 s, it is also a good choice to marry a girl aged 20 at the age of 40... on the first floor, I replied: at the age of 40, I found a young and beautiful 20-Year-Old girlfriend to go to her house to meet my parents. I opened the door to my first girlfriend who had been in college for several years. The new girlfriend shouted: Mom ~ [2 Floor] added: when her mom saw me, she was shocked and took a breath. I did not wait for my response, and then pulled my daughter into the room and said to her, "You cannot be with him. He is your own father !" [Third Floor] continued: Female: I already have his flesh and blood ...... On the 4th floor, the girl's 60-year-old father came out and saw the girl's boyfriend. He whispered to him, "Why did you come, didn't your mom and your living expenses be paid on time every month? [5th Floor] "ding dong", the girl's boyfriend's mother came to see her. Seeing the girl's father: "Why are you... "[6th Floor] when the girl's boyfriend's father stops and goes upstairs, the girl's father immediately enters the door:" Aren't you my brother who has been lost for many years? "[7 th floor] the girl's mother saw her boyfriend and mother:" Mom! "[8 th floor] when the girl's mother saw her boyfriend, his father shouted," Dad !", Fainting immediately 1. How many floors do you understand? 2. What is the name of his mother's father when she sees his mother's girlfriend?