He shouldn't do that. My daughter was raised up

by her grandparents till she was 1 yer and 10 months. I spent one and half years to steer the bad habits. I can't say I succeeded completely, but at least she's turning better.

When she came back a year later, her daddy brought her back to visit grandparents for 3 weeks. After she came back, I was so supprised to see how spoiled she was in just 3 weeks. I spent almost two months to change her back and felt sooo exhausted. So I decided not to let her visit them at least in two years.

I don't agree those people who say wait till your father goes back to China. You should tell him straightly that he should not be in charge of kid's education. Old parents in China always try to interfere their offspring's family. They think they have the right on educating their grandchildren. But, in deed, they don't.

Just to let you know my lesson, my daughter got time out almost 4 days a week after she visted her grandparents in the first 4 months. from then to now (3 monts) the frequency of time outs she received was reduced to 2 times a week.
If your son can't receive proper education, he will receive more time outs or break from school. Such as picking nose. My daughter didn't have these maner either and she received break for this EXACT reason.

My parents-in-law was supprised to know that my daughter was having a lot of breaks. They can't understand how their sweetheart can do anything bad. So am I confused how they can't see how much they spoiled my daughter.

Anyway, you should seriously talk to your father, or you will need to put extra extended time on teaching your son proper manor.