OK so on the windowsill outside of the bathroom in my house is a robin nest and my mom claims that she hasn't seen the mom come back for a few hours. When we looked at the nest, the 2 baby birds looked like they weren't breathing and they were stiff, with their beaks up in the air. The the one was breathing heavily. Are the other 2 dead? Is the other one going to die? Did something happen to the mom? Should we try and help the babies??

PLEASE help us!

Feed them mushed oatmeal out of a syringe... I am not sure!!
Look online!
Something like regurgitation!!

In the past, I have raised chickens, as well as a western jay and a crow, and saved countless other baby birds before transferring them to rescues. If they are stiff then, yes, those baby birds are already gone. Breathing heavily, like they are panting, is also a sign that the other baby is weak and dying. Usually, once baby birds start that panting, they are almost surely going to pass away. I still would not give up hope, however.

If the babies are already in such a state, chances are, something did happen to the mother, yes. If you can help the surviving baby, at least comfort it. Young baby birds die without warmth before they die from starvation, so holding it cupped in your hands should make it feel safe and warm. If you happen to have an electric heating pad, those are great for keeping babies warm, although beware of letting them get too hot, as that can kill them, too.

With my crow and western jay, when they were young, I fed them canned dog food from a small syringe. It was soft and squishy, similar to regurgitated food from the mother.

Thank you! Sadly, we found a baby on the ground, one of the dying/dead ones, and it was obvious that something killed it. Another one is dead too. We only know of the third baby that remains alive. We see the mother sitting on branches away from the nest. She isn't coming back very often!

Or could we put some worms into a food processor with some water and feed it to them?

Stay away from worms. What you need to do is get some soft fabric and something of a nest-like shape small enough for the single baby bird. Be aware, that with only one of them, if it survives it will imprint on you and you will not be able to release it into the wild. So, take some cat food, add warm water, and wait for it to be mushy. Hard boil an egg, and then squish it up along with the soggy cat food and some apple sauce, until it's as mixed as possible. Next, takes something basic like a tums (for stomach aches) and cut about a quarter to a third of it off. Crush that quarter to third, and mix the powder with the gross cat food/egg mix. Feed it to the baby carefully through a small syringe. Depending on the age of the baby, it'll need to eat every two hours, though once it's old enough it will let you know when it's hungry.

We found a baby sparrow fallen from its nest last summer, and were able to successfully keep her alive and raise her with this food until she could move on to adult bird foods. She was panting, as described, when we found her. More detailed info here. :3

Well, it is about a week old. We are already feeding it chopped up worms, and it's doing fine. He's even falling asleep.
Also making a baby bird eat something with hard boiled eggs is kind of disturbing?? Thanks for trying to help, though!

PS: If you haven't already got it yet, we already brought him in our house.
His mother is not dead, but his two siblings are. The mother, however, is not calling for the baby, feeding it, or even tending to it.
Now I didn't do this, so don't critisize, but my DAD grabbed the whole nest and put it in a bucket. We have two dogs, and my dad wants to acquaint them, so that our dogs don't eat it. However, me and my mom voted down on that because we agree that our dogs may eat it. We looked up online that if a baby bird grows up thinking dogs aren't a threat- well, one day it will get to the age when it hunts on it's own- and it may grow up thinking all dogs are not vicious.
Unfortunately, me and my mom also argued between our dad on another thing.
The bucket that the baby's nest is in isn't TOO big, and he could possibly jump high enough to get out of the bucket while we are sleeping. He thinks nothing will happen.
I may get back to you all with a picture!

http://tinypic.com/view.php?pic=2i1czr&s=8#.VX97pvlViko
And here is a picture!

For the sake of the bird, here.

wow Eimell, have you raised birds before?