Anybody else raising their grandkids?

I am in the same boat. We are raising two of our Grandchildren. One from my Stepson (7 yr old boy)and one of my Stepdaughters kids(5 yr old girl). We have had custody of them since they were born. Both step kids don't have the sense to come in out of the rain. They were brought up right but choose to not do the right thing or make the smart decisions. We get absolutely No help from either of these kids in supporting the upbringing of these kids. It is very expensive and not fair to have to be doing "Round Two" so to speak, but what can you do? It is not the kids fault... they never asked to be born and we decided it would be better for us to raise them instead of them going to State custody.