Does renting a house make people laugh?

My wife and son went to my father-in-law's house. When my son got there, he was so tired that he fell asleep just after eating, and then he was taken to grandma's room to continue sleeping. After playing for a while, we saw that it was getting late and left home. I always felt something was wrong along the way, but I couldn't remember what was wrong. When we got home, we remembered that our son was still sleeping on grandma's kang. ...