Maybe teach him to come inside without them having to go outside by using an incentive. They could split his daily rations into about 5 or 6 small portions and feed him one of these when he comes in from the yard.
To get him to realise that the food is available, they could buy a whistle or small bell, something he hasn't heard before and ring/blow it just before they give him his food. This is the only time he should ever hear it.
His food should then be given to him emmediately...within 2 seconds of the sound or it won't work.
Soon, when he hears the whistle/bell, he'll automatically start drooling even if no food is on the go. If he is out in the yard and he hears it, he'll come inside pretty quick to find the food he's expecting to be on offer. If he is drooling and he'll have no control over this, it happens automatically once they are conditioned, he'll feel a strong need to eat in order to satisfy the urge that has developed due to the sound.
After a while, the food can be replaced with praise and they can start to call him by name after blowing the whistle/ringing the bell to get him used to that as a recall command but keep the food going until he has developed a good recall despite it. If the food stops when he hears the bell/whistle, the salivating reflex will cease fairly quickly but will remain while ever food follows that sound.

Does he only act aggressively to her when she tries to bring him in? Usually, this is because the dog is frightened for some reason. Maybe the body language she is displaying looks threatening to him. I remember one of my dads border collies being like this with my oldest sisters ex husband but he was crap with dogs and was too overpowering and impatient for her. When my other sister went to get her for him, she was fine with her and would be with me also even though she doesn't see us that often.
The other possibility is that the dog percieves her hubby as being the most dominant and daren't mess about with him but will try it on with her if he views her as being less authoritive and weaker....not just physically but mentally.