How do I get my dog to stop barking when he hears our overnight guests?

We recently adopted a cairn/scottish terrier mix. He started out adjusting really well, and was very well behaved. My brother in law moved in 5 days ago, and the dog has started chewing on furniture, whining, and barking incessantly whenever he hears him at night after we've all gone to bed. How do I help him adjust to someone new living in the house, and stop him from barking and waking the whole neighborhood up?

Asked by Member 1113450 on May 31st 2012 in Barking