If you can't freeze him, do you have any woods nearby where you can bury him or something? Maybe do a little service with the kids and lay some flowers on the ground? Otherwise... well, if the body isn't frozen then things aren't going to be pretty in a short while.

I will leave him outside for the night in his box. The temperature is low tonight and tomorrow. This way he would be part of nature. I just can't stick him in the freezer. Thank you Cloudy skies.

If the weather is cold then putting him outside will be like natural refrigeration and that's a good thing. Be sure to put the box in a place where dogs, cats or other animals can't get to it.

Windows and sliding glass doors are dangerous. Birds don't understand the concept of glass very well and think that it's open space. Even if they've learned that there's a solid surface there they might forget when they're spooked and fly into it. Depending on what kind of blinds you have, you might be able to close them enough that the birds can see that there's a barrier there, but not close them so completely that no light comes through.

If these were my birds I'd do a light clip on the parents and the older babies. I'd let the younger babies stay fully flighted for a while longer if they're not behaving too dangerously. But if it looks very dangerous I would clip them too. Staying alive is the top priority.

I am so sorry you lost little yellow back.

Thank you, Dianne. He would be a great bird.

I can tell how handfeeding goes, better to say doesn't go.
Usually I am not able to feed them right after they get up (busy with other things) I am serving a table for all birds, feed the rabbits, feed daughter, take her to school, finally feed myself.
When they get up, it usually takes them some time to figure out they should come to eat and feed the kids (they all wandering around and so on) - this is when the kids are hungry after the night. Anyway, by the time I am available to handfeed them, they all have eaten food on the table (including the babies) and father got into feeding them pretty well. I make formula that looks yummy at this particular moment. I take Babyface first as he always ate well from me. But now he flies from me. I have to practice some gymnastics getting him from all the high places he lands at, formula becomes not so yummy, I get pretty dirty in my attempts to squeeze formula in his beak, he gets dirty too, and all other birds sitting just outside this room screaming for him and we can hear feeding noises that father makes to other babies.
The second is Greyback (all nicknames so far) - same story. Formula is not yummy at all by this time but I still have a full cup. By the time I decide to let him go, my mind is totally sick to even think to do the same to Cinnamons who never ate from me.
I wish I could feed them at different time but it's not that easy.

How old are they now? I wonder if they might be more or less weaned. It sounds like they're getting enough to satisfy them at breakfast time at least. Do they beg the parents for food a lot or do they seem fairly satisfied most of the time?

They are around 6 weeks old. Some are already 6 weeks and others will be in a few days. Yes, they beg daddy for food a lot but they also eat a lot on their own so overall they are satisfied. Mommy is out of the feeding game long ago. I found an egg in the living room on the floor which means she gave up and just released it from her body. Also death in the family probably threw everybody off a little bit. They froze in the kitchen for an hour or even longer when it happened - no moving, no eating, no chirping, just sitting quietly.
They all weight 80+ g, which is better than our previous clutch - those birds went down under 80, like 75g and such. I have a feeling dAddy is feeding them pretty well for their decreasing needs.

Another moment of frustration: I made formula and come to grab a baby, but they all are eating seeds, pellets, millets and such. At a moment like this, I think I should leave them alone, because learning to eat is very important.
Today I needed to handfeed two (I "did" two others earlier): one was eating and another was sleeping waste of formula is huge here.

They're definitely not weaned yet but it does sound like they might be getting enough to eat through the combination of dad's help and their own efforts. It's definitely better to not try to handfeed them when they're busy feeding themselves. If there's a time when they're crying for food and dad isn't satisfying their needs, that's the time to go for the handfeeding formula. A baby that's frantically crying for food is usually too upset to think of feeding itself and could use some help. But if it's just not possible to handfeed at that time, you could stick a piece of millet spray in front of its face to remind it that this is an option.

Thank you. Yesterday Cuddles laid another egg (third). I heard a sound like something fell. I came to see what it was, and it was an egg on the floor while she was sitting on the ceiling fan. I wonder if she going to stop. Eventually she doesn't care to lay them in a safe place.
I figured out which babies have their weight stable and even increasing, and which are not so successful in feeding themselves. The two youngest need assistance, which is even logical Babyface is eating formula well. I am trying to find a way to feed the smaller Cinnamon a bit better. So far, the only way she would eat is when I let her fly and she lands somewhere, then I can feed her there (very inconvenient) . This is exactly what our older clutch did. Eating sitting on the open doors of the closet. It works much better than when they are on the curtain rod Of course, its a bad way but at least it works. Babyface eats on the table.