While you live in their house, yes, they can tell you who and who not to talk with. All you can do is ask for their reasons and try to convince them that you should be able to.
No they can not. But they can put pressure on you if you live in their home and support you. At 18 they are no longer obligated to care for you.
yes
Yes.
well if you are in college, you are most likely 18 and a legal adult, so you can technically date who you want. but if they want you to stop seeing him, it may be because they sense something off about him. talk to them honestly, and if what they say about him rings true, maybe you really should stop seeing him.
yes they can a restraining order
slap him in front of everybody or tell your parents .
Depends, what did he threaten him for?
You can encourage him to stop selling drugs, but you aren't going to make him stop selling them. You could stop seeing him and find a guy who is not a drug dealer.
well, If your parents want you to dump him, he must not be that great of a guy. They want the best for you.
No because the boyfriend has a legal obligation to this child whether the boyfriend is under age or not. His parent do not have a say in it at all. Your boyfriend is now considered an adult in the eyes of the law were your daughter is concerned.
If it's affecting you negatively, you should discuss seeing other people. Being in a relationship & his parents should not stress you out to the point where it takes its toll on you.
I'm not sure who you mean by him, but I'm guessing an ex or boyfriend. You can't really stop anyone from seeing anyone. You can talk to him about it if you want, but there isn't really a way to keep people from dating others.
That depends on if it bothers you or not? If it does tell your friend. If she is a true friend then she'll respect your wishes and will stop seeing him.
It depends what you mean by 'of legal age'. Your parents have control until you reach your majority.
Either make sure that they never find out about each other, or stop seeing the one you only 'like' - what sort of love is it that allows you to have another boyfriend?