Test your skills
In New Zealand workplaces being able to communicate and interact with colleagues and the boss is very important if you want to fit into a team. Most new migrants find this a challenge, especially when it's the boss who greets them.
If you were John, what would you have done in this situation?
Nothing. If Robert can't manage a simple conversation he's not going to fit in very well.
Tried to do a bit more to put him at ease - asked him about the weather or his plans for the weekend.
Mentioned to someone in Robert's team that Robert shouldn't be frightened of him and it's OK to speak to him.