The mother doesn't care for her babies so they don't need her for anything though she may have died because she was egg bound, they don't generally prefer to lay their eggs in the water (they dig in the sand). Not all eggs are viable to begin with though if she was around a mature male in the last three years or so (they can store sperm) it's possible. Moving turtle eggs can seperate them (attached on the inside) so that they aren't viable, if they've been floating around in the water there is a good chance they were jostled or turned and not viable anyways. Here is a turtle site for you.
www.austinsturtlepage.com
www.austinsturtlepage.com