Is there anything I can do to stop a mentally ill cousin from stalking me online & mailing me cards?

Block her email address. I doubt you would have a case for "sending you blank holiday cards."

Two year statute of limitations for for intentional interference claims Cal.Civ.Proc.Code § 339(1).

Can my son sue for slander?

Need more facts, but at first blush it seems like he should hire an employment lawyer and not consider a defamation suit based on these facts.

Landlord tenant the landlord is accusing me and my fiance for breaking in his gradge

You can, but I can assure you that you can't afford it. Either that or you're just illiterate and wealthy, but the two don't go together very often.

Can someone be sued for libel for posting that a coach got fired?

Libel requires an unprivileged false statement of fact that harms the subject's reputation. I am not seeing defamation here, if the coach was...

Do I have grounds to sue for Defamation, Slander or Libel?

Defamation requires a false statement of fact. I'm not seeing you claiming that he said anything false, just that he has a bad opinion of you.

Been wrongfully accused of theft and don't know if I should get police involved and ruin my reputation.

An erroneous police report is not usually going to support a claim for defamation, as the reporting party has a privilege in that report. As long...

What the colorado law say if someone has been slandering me with nothing information or by fabricated story? can I suing or no

Saying someone is "gay" is likely no longer defamatory. A recent case in New York held such. Colorado has no decision directly on point, but I...

My Dad is mad and trying to threatin to call dhr on me and sying i had sex with my 14 year old step sister which is crazy

So what is your question?

Is it illegal to write lies on facebook and how can i stop it

I agree with Evan. You need a family law attorney, not a libel attorney.