It really is impossible to put into words that you'd understand, simply because of all the "family dynamic" that it involves, but to break it down to its simplest form, he essentially went against his VERY religious fathers wishes regarding certain aspects of his religion. Again, it was nothing bad, like premarital sex (bad, as in the context of this family), drugs, or alcohol abuse or anything like that. To break it down even easier, it is the equivalent to the son breaking family Republican tradition and registering as a Democrat, only with more fireworks. The kid was simply only doing what he has always done, tried to do the right thing, that would benefit everyone, and of course it blew up in his face and the father/family disowned him for it.
I laughed, but then cried.