To keep your supply going, particularly in the early weeks, you would have to get up while he's feeding the baby anyway to express, so it wouldn't actually help you get more sleep. Plus, personally, I could never sleep if I could hear the baby crying/awake, so would have ended up being up during the feed anyway. It's lovely that he wants to help, but I would have a chat with him about what would really be a help to you (and revisit the list after the baby arrives). Feeding isn't the only (or, in many cases, the most practical/best) way to help, and certainly isn't the only way to bond. Little things which I really appreciated dh doing for me were:
Packing the changing bag the night before so I could just pick it up and go in the morning.
Putting out a playmat and toys in the lounge before he went to work so that when I finally made it downstairs with baby I didn't have to faff around finding toys.
Changing nappies (it's not glamorous, but then not much about the early days with a baby is!).
Taking baby and getting them dressed in the morning.
Taking baby off me after he'd had one breast and changing his nappy, before he had the other side.
When he got in from work, he'd take the baby off me and take him upstairs for half an hour/an hour, so he got time just him and baby and I got a luxurious half hour to drink a cup of tea.
Making you a lot of cups of tea. Providing endless food (breastfeeding can make you reeeeeealllllly hungry).