So sorry the baby didn’t make it. It’s tough when you do all you can and they still don’t thrive. I’ve had babies before like that. Ones that I had tried everything for and it still wasn’t enough.
It’s hard to tell from the video but when I have a chick that can’t stand I try a chick chair. I allow their feet to touch the floor in the chair in the hopes that their leg with strengthen. This has worked for some and not for others.