Thank you to everyone for your kind and supportive comments about Brian. It is really helpful. When I posted what happened, I worried about receiving mean comments that would only make me feel worse (if that's even possible) -- you guys are the best.
I miss him so much! He was such a special soul and I wish I would have had him for many more years, but I know I need to treasure the time I had with him. I'm happy that I have so many photos and videos to remember him by. I'll post some more in the future, when I'm feeling up to it.
I spent much of yesterday sobbing, so far today it's only been tears leaking out. Luckily I have a very understanding boss and no customer contact! I was even able to sleep through the night (after being unable to sleep Monday night), though most my dreams were about Brian.
I think one of the things that pains me the most is that I thought I had taken every precaution. I've relived the experience hundreds of times in my head, and there's nothing that I would have done differently under the same circumstances.
It's made me question whether I should ever own another budgie. I can't imagine the rest of my life in a budgie-less existence, though I'm certainly not ready to add another one at this point. The woman who runs the rescue suggested that I look into acrylic cages or other ways of adding an additional safety layer. This is something I will have to look into in due time. Right now it's still too raw.
Max and (surprisingly) Basil were very empathetic yesterday as I was changing their foods and waters in the morning. Max would not leave my side and made frequent kissing sounds. Basil kept softly repeating, "I love you Basil" which is what I tell him when I'm trying to comfort him. They could tell something was wrong and were trying to cheer me up.
Anyway, I will try to get back to regular posting tomorrow. Thanks again for your compassion -- it means a lot, more than I can express.