If your "friend" got married in Las vegas she is married now to that person. That marriage is and continues to be valid in every state.

The marriage is presumed to be valid unless it is later set aside. Being drunk does not make her "not married". Being "drunk" would be a factor in her attempt to invalidate the marriage afterward. She would have to have proved that she was drunk. You cant just decide later that "i was drunk so it doesnt count". Dont know the period to annul the marriage in Las Vegas. I doubt that 20 years would allow an annullment. She should contact a lawyer in Las Vegas and correct this now.

Your friend was a fool then and continues to be one now. She should grow up and take responsibility for her actions.

as an aside she can always find out who she married and then someday claim benefits such as social security.. if you are married to a person 10 years you later can get those benefits or maybe her husband can enjoy benefits based on her assets,, foolish people create great issues..and then she can complain about the legal fees. blaming lawyers for her problems.