DH goes away on business from time to time, usually for about a week at a time. The dog barks for about 2/3 hours at night when he goes away and keeps us all awake. He sleeps in the kitchen and is not allowed upstairs (new carpets!). I've tried going down and talking to him, letting him in the garden, turning a light on, shouting at him
. None of it works so last night I just let him bark it out which he did after about 3 hours. 
What can I do? I'm exhausted but more than that I'm worried about next time DH goes away as my parents are coming to help me with the school runs etc as DH and I usually share these as we both work outside the home. My parents are in their 80's, don't like dogs much and like their sleep a lot. 