Undermined By A Co-Worker

I recently graduated from college and decided to go into the real estate market. I have been lucky enough to have a boss who values my diligence and research skills. As a result, he gives me more leads than he does his own son who is my coworker. There is definitely some animosity rising and I have noticed lately that he is trying to find ways to undermine me and cause issues. How can I handle his behavior and continue to be an asset to my office? Could any action I take with the boss's son sabotage my work here?