As I was a nurse and had worked in labour ward as an auxiliary, I was pretty prepared for labour-although still really nervous! 
DH arrived when I was 8cm, with his little bag of drinks, nibbles and book...god love him, he never even got to open it!
Tell him to get snacks, drinks and something to read/do, maybe pack of cards?
However, I have a real thing about a birth partner being just that-a partner. It is not a floor show, where he stands around looking useless and wishing he wash"t there. Does he know your birth plan-he needs to know what is going to be happening, and speak up for you and your needs/wants if you can't.
Does he know the contents of your bag, does he know what breast pads are? Does he know what maternity pads are? Baby vests? Babygros?
I would get very agitated if DH was standing around looking helpless after I had just been through labour!
If he wants to be there, then do the research and homework. My DH did read the stuff I gave him, and held my hand, rubbed my back, gave me sips of water and was very supportive. But I knew he wasn't "enjoying" it IYKWIM. Which is why I had BFF as partner for DS2 ,and will be having a really good friend as partner for DC3, due next month. She is coming over the do birth plan with me tomorrow.
I'm not sure if the hospital would have any shower facilities etc for DH. But many wards do provide a kitchen area for tea & toast.
Good luck!