There will be beeping booping noises and alarms, and a lot of ignoring of same. This, too, is normal.
Bring a blanket for loved one. Hospital seems to be happy to give sheet after sheet, and will sometimes warm up the sheet, but actual blankets don't seem to be a thing.
If you're left handed, say so. If your loved one is left handed and not currently able to point this out, do it for them. If the hospital is putting a line in, it's better if that can be done on the non-dominant arm, and it probably can, if they know.
If hairy, ask for a shave of the area. This will make the tape or electrode back or whatever less annoying.
And understand that the doctors don't hate you if they take a long time to see you. They have rounds and lots of other people to see. Yes, it's okay to check with nurse on duty or whoever is willing to help out to make sure they are still en route and haven't forgotten, but do your best to balance this. (I'm not talking about emergency situations here, just the regular hospital stuff.)
If there's a time frame, make sure they know -- e.g., saying, "I'd like to head home at 6" may well have helped get us a visit from the neurologist around 5:30 with results on the EEG.
Taking notes is a good thing. So is writing down questions you want to be sure to remember to ask.