Things to do
Be clued up as to what she wants in her birth plan and be ready to speak up for her.
Have meals pre prepped
Don't let visitors outstay their welcome. Cancel them if she's not up to it.
Take baby out for a walk to give her a breather.
Encourage her to see her friends when shes ready.
Have things she loves in the house - food, drinks, treats etc.
Make it easy for her to just sit and feed baby and rest when she can.
Time together, to see each other but also to talk about how you're both finding it all.
Keep an eye out for signs of pnd developing.
Tiredness can take its toll on both of you, be mindful that you're both knackered and your responses to each other might not be what they'd normally be.
Things to get
Make sure she's got more maternity pads than either of you would ever think she'll need - though nighttime sanitary pads were more comfortable.
Lansinoh cream if she's BF.
Books and box sets.
All the snacks (healthy and not - there's a time and place for both).
I'm a firm believer that you don't need all the fancy stuff for a baby having had 2 that hated the bouncer, swing. Pram and life itself but having a supply of metanium for sore bums, infacol/colief for wind, nasal aspirator for colds can make life a little easier and save a mad dash trip to the supermarket when you're in the midst of mayhem and need one of them - and it's not a lot wasted if you don't then need them.
Try various different brands of nappies, you'll find ones you prefer and fit baby better.