Can I join please? My 10 year old has had 22 hospital admissions, mostly when he was 5 and under but he is currently on the waiting list for 2 different operations. And I have inlaws who keep going on about how stressful it is for THEM (I only asked them to look after my 9 year old for an hour and get him to school so hardly taxing. We even said no worries if not possible, it would just be easier if we didn't have him with us.
Anyway, my tips are to bring lots of stuff for your entertainment because it can be really boring (although a lot of people are horrified that I get bored, apparently I should be content with watching ds sleep and they would be too worried about their child to read a book).
Take photos. DS always asks what he looked like "when I was poorly" and "when I was asleep" so it's nice to be able to show him. I didn't take photos of my older child covered in wires because I was worried the nurses would think I was weird. Then a few days after he got better he was asking questions about what happened while he was unconscious and I wished I'd taken photos.
pyjama fairies do hospital gowns/pyjamas for children in lovely bright colours
Really smelly lip balm smeared on the top of the anaesthetic mask makes the gas smell less awful.
Bring your own paracetamol/ibuprofen if your dc doesn't like the cheap, own brand stuff that most hospitals use
hospital bracelets for your child's teddy can be bought on amazon.
My 10 year old has a name badge on a lanyard with his photo in that I made him years ago. He loves it and it makes him feel like he is staff and has control of his treatment.
Keep a suitcase packed with more clothes, books etc at home just in case you have to stay longer. Then you can say to someone to bring the suitcase. I learned that trick after asking dh to bring me stuff and he brought me a pyjama top instead of a normal top, trousers too small that I was hoping to fit into one day etc!
Bring your own pillow. Pillows are always getting nicked in hospital, although goodness knows who would want a plastic rustly hospital pillow!
I'll try and think of some more later.