Bird hasnt returned to its nest in a few days, babies are alone, what do I do?

There's a house finch's nest on top of a lamp outside my house. My brother's are always making loud noises and scaring off the mom. However, I havent seen the mom in about 3-4 days now and it seems that the babies have hatched since today is the first day that we are able to see little beaks. Im worried about the babies since there's been no sign of a bird stopping by their nest. What should I do? Should I wait another day to see if the mom will come back? Or should i try to help them?? Thank you!