Is it legal to be audited by a social worker when there is an agreement? 1 Answers as of February 09, 2012

I have 3 kids that are currently staying with their grandparents. (Mother side), but I still hold the full custody of the three kids. I help the grandparents once or twice a month economically. My mother used to watch over the youngest one for over 6 months, and now that she doesn't she requested a social worker to audit the kids grandparents, and me as well. My question is, is it legal to be audited by a social worker even though the kids grandparents and myself have come to an agreement?