You sound like a lovely, caring sister, OP. Congratulations on the birth of your niece, and sorry to hear she arrived so early. That's a great weight for a baby of that age, by the way. I'm glad to hear they're both doing well.
My daughter was born at 29 weeks. What I appreciated most from people who lived far away were actually just regular phone calls and texts asking how we were all doing, and allowing us to talk about it as much as we wanted. There's quite strong social pressure to minimise how difficult an experience having a baby in the NICU can be, and it was great when people just let me chat about any of it to my heart's content!
I was sent quite a few tiny clothes but didn't actually get to use them much, as many of them weren't really suitable for a NICU situation, and then she grew out of them so fast once she could actually wear them. Your sister's baby's situation might be different, but it might be best to check with her first.
Things I did use and would have loved to have been sent: nice hand creams, blank photo album, pretty notebook for recording baby's progress, trashy magazines, and, yes, lots of snacks! We weren't given any soft toys by anyone, so I had to go and buy a comforter myself for her incubator - that might be another idea (just make sure it's washable). I was given a (washable) hand-made baby quilt that we used to drape over her incubator during the day, as they need to be in the dark as much was possible when they're that young. I also could have done with a few spare breast pump sets (so as to minimise washing up between expressing sessions) but didn't feel I could afford the cost at the time. I also should have bought a steriliser.
If you're able to go down, I'm sure she'd appreciate help with shopping, batch cooking, washing up, laundry, etc. (possibly childcare if she already had DCs). We found trying to keep up with basic chores really stressful as we had very little time left after visiting the NICU, and expressing took up pretty much any spare time. This was the case while I was in hospital and also once I was back home.
I hope some of this helps. I'll be thinking of you all OP and hoping for continued good health for your sister's baby
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