I'm going to use the same phrase that DoggiesAreTheBest used.
It pisses me off also that someone could do this to an animal. Can't come inside cause he will dirty the house. I have never heard of anything so ridiculous in my life. It just breaks my heart thinking about this poor dog out there, looking at the house and wondering what the hell he did to deserve this inhumane treatment, while the other spoiled brat has the lap of luxury.
I hope you find a good home for him where he will receive lots of love and attention, and i'm sure you will make sure of it also.