There is a group in Boulder called "Grandparents raising their grandchildren", sponsored by the city. I attended a couple of their monthly meetings. I am not really raising my grandchildren, but I do take care of them 9 hours a day for the 5 work days. My son and his wife cannot afford day care for the twins, so we have been doing it now for 3 years.
I stopped going to the group meetings because it was essentially for grandparents who had full control of the grandchildren usually because of drugs, jail or alcoholism of their children. The participants of the group were very open in telling us of the problems of their children.
None of the friends I grew-up with were foster children or raised by grandparents.