I would always leave him to sleep. Both my boys woke for night feeds, I never woke them and they eventually dropped them on there own. Isaac dropped his last night feed (well 3/4am feed) about a month ago.
I've never had a child capable of dream feeding though, when they are asleep they are asleep no amount of putting a bottle in their mouth was going to make them take it. They just got grumpy at being disturbed.