If my limited experience is anything to go by, the amount of bridge building (and bridge repairing!) that these tiny ones do, would merit membership of the Construction Industry Federation
From having watched others and been the parent of the a little one, I would say that any vote of confidence in the outcome for a premie is a great support to the parents - there is a marked reluctance on the part of people to congratulate or buy a pressie for the baby when these might be the very things that parents need to feel that they are not living in some sort of land of total delusion when they hope for a positive outcome. If things don't work out as they had hoped, the parents will deal with that at that time, however as Beanie said, the person who clearly shares the optimistic perpective is most welcome company!
I know that,in our case, the few people who went out and bought small things early on, were most welcome, as was the support from the magicmums.