They are still very nervous about something happening to their baby.
Preemies are at a very high risk for contracting
RSV, and can die from a virus that would cause a cold in a full term baby.
There are lots of things you can do to help preemie parents, so just be creative. Also, you may have to be a bit pushy with them, and rather than asking "what can I do?" you may have to just tell them "I'm going to xyz...