@jcharlie85,
First of all, I am not a doctor or any kind of healthcare provider, so don't take the following as the opinion of a medical professional.
If she truly hasn't used anything in a month, then I don't think she has anything to worry about.
The problem is that drug users very often are not honest about their usage.
I found this on Meth and surgery and it involves, ostensibly, a doctor's opinion.
I don't offer it as authoritative or suggest you rely on it as such. I do suggest you do more research.
The other drugs you've mentioned, again if you have the time frame right, should not have remained in her system after so long.
If she has not taken any drug for the last month and she doesn't take any before her surgery, she should be alright,
but she will still be potentially gambling her life, and
if she is specifically asked the question in pre-op, she should tell the truth.
You can do more research on the web and will likely find the same information. I know if I were you or your friend I would, because I wouldn't want to, necessarily, trust the word of a strangers who admits he's not a doctor.
Regardless, this information should abate, to some extent, her fears about the effects of drug use prior to surgery. If it doesn't, she is either normally paranoid (possibly because of drug use) or she is not telling you the truth about her last use.
Whether or not doctors are required to report admitted drug use to the authorities is something I've no information on. I think it's unlikely but I know the Feds (no matter who is in the White House) keep cracking down on drugs (no pun intended). If you haven't goggled the phrase I gave you previously, I strongly suggest you do.
What admitting to illegal drug use might result in, if not reporting to the police, is a modification in the standard post-op prescription of painkillers.
I personally believe all drugs should be legalized but
I do not recommend everyone, or anyone take drugs, and using Meth, in particular, is a crazy path to death. Pot and LSD are something else, but she's obviously moved on from them which is one of the problems of drug usage.
If she were my friend, I would advise her to answer all questions posed by her doctor truthfully. They don't ask them in order to trap drug users, they ask them for the safety of the patient, and, to a lesser extent, to protect their butts from litigation.
And I would recommend, strongly, she never use Meth or Crack again...never.
If she wants to get high, she should stick to pot. It's not without it's side effects, but it is a whole lot less dangerous than the other things she's been taking.
Everyone is nervous before surgery, but if she's really scared, I would suggest it's because she is still using.
Good luck.