Like Nat said, keep them separated. He could stay fertile for the next few weeks. I would keep something between them so they can't see each other if he's getting upset. He may calm down.
Check on the bunnies about once a day when the mom is not feeding them. She will only feed them twice a day (once in the early morning and once in the late evening). They should be warm and have have full bellies.
I'm sure it's hard not to constantly check on them, but the best thing to do is let them be so the mom won't get stressed out and possibly even stop feeding them as a result.
I would start contacting people who may be interested in adopting a baby. Be sure they do their research, and it's usually best if they don't have young children, cats, or dogs that could hurt them. Telling them about YouTube channels such as Lennon the Bunny, 101Rabbits, and The Bunny Lady, will help them learn what all is involved in caring for a rabbit.
Assuming the parents have been switched to Timothy hay, I would provide the mom with some Alfalfa. This will help her while she's nursing, and the babies will need to be on Alfalfa once they start to wean.