It doesn't matter what you do as long as you do something . Stop a little while. Ask her if she wants you to stay or leave her. Sit quietly with her. Let her talk if she wants. Offer to accompany her if she wants to go anywhere, drive as she may be too in shock.
Like others said cooked meals in freezer or fridge are good, fruit , biscuits, cakes , smoothies, little porridge pots, are good. Friend probably won't have an appetite or not be able to taste her food for a while, grief turns food to ash in your mouth.
One of my vaguest memories is a friend bringing a fluffy blanket round (so I see where you're going with fluffy socks) and leaving it folded up on back top of my sofa.
When I wasn't in bed howling or keeping my eyes closed to shut out the nausea , I wrapped myself up in that blanket on the sofa, just staring vacantly.
I think id have gotten frozen through with barely noticing as it was hard to move, i lost hours and days, so I really appreciated that little bit of warmth and softness. (I had other blankets around the house but my head wasn't working) but somehow that little colourful blanket became important to me. She did it well though, she left it folded without saying anything.
Im sure she also cooked for me, cleaned subtly, emptied dishwasher, put laundry through, picked up post all very quietly- I'm sure I fell asleep a lot when she was visiting.
But she always texted me before coming round -"dropping by in half hour if that's ok.. you can leave me on doorstep or open your door let me in and I'll make you a cuppa ." She was never noisy unless I was (we laughed hysterically at some things that were just ironic but I led that..)