please help on parents' visa

My son is living with my parents in china now, I want my parents to apply visa and take my son back this year. I wonder when my parents fill the visa application form, do they need to fill in my son in the form. My thought is since my parents have other grandchildren, and they will not fill the other grandchidren in the form, the same thing goes to my son. Of course, if they are asked if we have kid, the answern is yes. If they are asked where is my son now? How can they say? My son is taken back by my mother in law, can they say my son is living with my mother in law instead of saying living with them, I am afraid if thye say my son is living with them, the officer will think they want to get visa to take my son back and will stay here for ever (of course this is not true, but sometimes the officer will think in this way and reject people based on their thought).

Thank you for any information shared.