Ask him! He is your child and if you think something is happening that could hurt him, don't let it keep building. He may be mad at you for seeing his "private" comments but you should be able to be honest about how you saw them. Its not as if you broke into his apartment and got on his computer. This is a room in your house and you have every right to be looking at comments that are up on a computer screen that you most likely bought. The small amount of resentment he will have for you seeing his Facebook page will be nothing in comparison to the relief he will feel if he is finally able to tell someone he's being bullied. Open communication is key. If he denies any bullying, then ask what those comments were about. Let him know how much you love him and that you are concerned about him. Then make him clean his own room. If he is old enough to have a Facebook page, he is old enough to clean up after himself.
What would you tell this person: "My boss keeps taking credit for my ideas. What should I do?"
First of all, make sure to document all of your ideas just in case you ever need to prove that they were yours in the first place. Then, without being confrontational (because this IS your boss), simply ask him/her about it. "Do you remember when I came up with ABC project idea? I was just wondering you told everyone that was your idea?" If your boss tries to play it off like he/she has no idea what you are talking about after you have given all of your examples, it may be time to go to the next higher level. But, be prepared, once you cross that line, there is no going back. Sometimes coming up with an idea at work doesn't mean you will get the credit. It will just be for the good of the company, but if your ideas are helping to advance someone else instead of yourself, it may be worth it to you to voice your concerns to your boss's boss. Personally, I think you should be up front with your boss about your plan instead of going behind his/her back. If you've documented everything like you should've, you'll have no trouble proving your point.