Stephanie--I can't imagine how broken your heart must feel to loose so many little ones in only one month.
If is any consolation, now Korbee and the rest of them will play and fly about the Rainbow Bridge in happiness.
I'm so sorry for your loss of Korbee. He was loved and will always be remembered, and you'll see him in your other budgies sometimes, and be sad, but remember that he'll always perch right in your heart with a happy song.
Hugs and best of wishes to you in this awfully difficult time