@Angelslookingafterus it's miserable isn't it and you've got a week on me and yours must be worse if needed observing at hospital 😢
Their airways are so small and they struggle to clear them, especially if prem. We have found a dummy helps as means baby swallows the snot, but does seem to mean bad wind so swings and roundabouts. I was wondering about reflux too but I think it's actually post-nasal drip and he's choking on the snot going down his throat from the back of his nose 😖
He's still resistant to being laid flat so holding him/slinging him for most of the day to help drain the snot.
But honestly I think main thing is gonna be time sadly. Take any offers of help and get them to hold the baby upright and both of you get some sleep. Check minimum weights on any slings, usually at least 8lbs.
Also given he's struggled so much feeding it may be his latch is poorer than usual so when well and recovered you could look into underlying tongue tie. Can affect bottle feeding and contribute to feeding and potentially speech issues long-term.
Only other things I can think of would be keeping temp 18-20 and humidity around 55-60%, seems to help with the sneezing. And Snufflebabe vapour oil if not tried it?
Really hope out babies get better soon 🤞🏻