In my limited knowledge of bears,it is a very bad idea to shoot a sow with cubs because the cubs will die without her.
IMO the cubs will be fine as long as there in good shape If a sow was shot. Some states allow a sow with cubs to be shot, some don't. If the cubs are that tiny when they den up with the mother they won't make It through hibernation anyway. If there in good shape they'll make It just fine on there own.