"Furthermore, he has EXPECTED them to be resistent anywyas and that alone is reason why he doesn't succeed. But when I told him that, he would get very defensive! :-)"
LOL! Then this really is LOA at work. Focus + emotional expectancy = creation. Unfortunately for your dad, he created what he didn't want, because that was his focus.
You have to allow him to be, for his path is different from yours, and you can never know what is best for his personal evolution, in this moment.