My son and his wife get along very well with my other two sisters' and brothers' children and their spouses. They get together and play cards about twice a month. whenever they play cards, all of the leave their kids with their parents. Its fine for my other sisters but my grandson is the crying stubborn types. he throws tantrums and refuses to sleep overnight in my house. I have to always wake up at 4 - 5 in the morning when his parents come back and take him back to their house. It is getting very irritating for me.
I want to teach my grandson to behave and go to sleep at a proper time irrespective of whether he is in my house or his parents (we stay on separate floors of the same building). but because his mother i.e. my daughter-in-law is very bad at discipling, that boy is becoming a real brat. How can i go about disciplining my grandson without hurting my daughter-in-law's feelings?