Welcome to the Forum.
So sad to hear about the hedgehog – that must have been a horrible experience for you. Sorry to hear the hedgehog didn’t survive despite yours and the rescuers efforts.
Sadly, Mothers of young hoglets must die, or be killed all too often – many, I suspect without us ever knowing about them. All of you did the right thing trying to find the youngsters, but sometimes theres just no way of knowing where they might be. I understand that sometimes young hoglets are found in similar circumstances and some may survive – although there is a fairly high mortality rate among young hoglets even if the Mother is alive.
Yes, it would depend on how old the hoglets are, how long Mother would leave them for and so how far away from them she might be and also how long they might survive without her. If they were close to being weaned I imagine there’s more chance they could survive.
The important thing is that there must be hedgehogs in your area, so maybe there might be some way that you can help any other hedgehogs. Here, for instance, we try to link our gardens by making hedgehog sized holes in boundary fences or walls, so that the hedgehogs can more easily move between gardens. That way they have less need to cross roads, which are so dangerous for them. There is some more information about that here:
Many people here also put out water and food for the hedgehogs to supplement what they can find in the wild and/or try to encourage wildlife, including beetles and other insects, etc. which hedgehogs eat. Cat or dog food is fine to feed them.