What should I do with a bird's nest with eggs but no mother?

My lovely but hunter of a cat killed a mother robin. Or at least I'm pretty sure he did since he's been eyeing her the whole day and tonight, I heard bird noises and found a bunch of feathers. I'm not sure since I haven't found the body yet :/ It's dark outside, omegle  discord xender  but I will double check in the morning. What can I do for the abandoned nest? Is there anything I can do? I was considering calling a Wildlife organization but with the COVID19, I heard many places are temporarily closed. I wasn't going to let him out tonight, but I guess he woke someone else up instead. Argh. Anything I can do?? The results I found online weren't very hopeful so I'm hoping I can find something better here...