Very encouraging dd. lets hope and pray. I don't know what Lacrystol uses but but if you have some betadine or iodine or Veterycin you can spray that little place where the yolk sac was. Make the iodine or betadine watered down to look like weak tea use warm water.I think you'll be OK, it looks like he has absorbed most of his yolk. If he's running around cheeping, that's a good sign.
Keep us updated. I think if he makes it through the next few hours and fluffs up, he'll be fine.