While you might be tempted to take over as the caregiver, the truth is that Mom knows best. Your role as a pet parent -- and grandparent now -- is to offer support, make sure Mom and the puppies are safe, and everybody is warm and well fed.
Set up a safe place for Mom and the puppies to sleep. Ideally, that should be a room inside your home, such as the bathroom or the utility room. If this is a stray mom and pups you're caring for, bringing them inside might not be an option -- maybe you have other dogs or you're worried about ticks and fleas. In that case, even the garage or a covered porch would do. Provide them with a kennel or a box tilted on its side as a "home" -- the sides of the box will serve as protection against wind and even light rain if they're outside. A few towels placed inside can serve as cushioning and will help everybody stay warm.
Check on Mom several times a day when the puppies are first born. Make sure all the puppies are nursing -- which means Mom is producing enough milk. If you see one loner puppy eating less or always being pushed aside -- common in moms with more puppies than nipples -- you might need to intervene and bottle-feed the runt.
Feed Mom high-quality dog food. Not only does she need the extra nutrition to help recover from the birth, but remember she's also feeding the babies. If she eats the equivalent to junk food -- poor quality pet food -- that's what the puppies will get too. So feed her good food and in larger quantities than she would normally eat when not pregnant. Even better, just leave a bowl out so she can eat whenever she feels like it -- or when she manages to get away from the pups.