The best results are acheived by setting them personal goals, then backing off. Let them find their own way of achieving these goals. Meaningful delegation is key; you just need to ensure there is a joint vision of the final result.
Outsiders often have a problem when it comes to empathy. They are often divorced from what others view as good and bad. They may even defend people who are condemned by the majority. That frequently means that pretty much whenever they say anything, someone will take offence.
Try to imagine, if only for a moment, how they perceive the world. Try to uncover what motivates them. Try to understand how their distant and hard-nosed attitude leads to them becoming estranged from the rest of the team.
Just apologise – for anything. An apology indicates respect and also comforts them because outsiders tend to be rather sensitive when it comes to injustice. Such a gesture on your part will encourage them to approach you and others in a similar way.
-jk-