The answer to your question will be determined with accuracy only after a review of her medical records because there are many details that are important to consider. I would encourage her to find out if her treating physician thinks there has been a significant worsening of her condition due to the delay. And, I would encourage her to contact a medical malpractice attorney to review the information and see whether she has a viable claim that is worth pursing economically. As there is a time deadline to filing suit, she should contact an attorney in FL immediately. Good luck.
One of the primary considerations in deciding whether to institute a medical malpractice action is to consider what damages the alleged malpractice caused to the patient. Because these cases are extraordinarily expensive to pursue, experienced medical malpractice lawyers will generally advise against bringing an action that does not have significant damages and permanent consequences. This is because the cost of the experts will be more than your potential recovery in small damage cases.
Has the PCP determined that the delay in diagnosing your girlfriend excerbated an asthmatic condition that would have been more manageable with an earlier diagnosis and treatment? Will this lead to a permanent problem for her in the future? From your comments, it seems like she will be fine now. It might be worth it to contact those previous physicians and inform them of this diagnosis to help prevent future such acts to others.
You may also run into a problem with the Statute of Limitations. Many states have what is called a Statute of Repose. This law states that a claim for malpractice may not be brought after a certain period (like 3 years from the date of the malpractice in Louisiana) regardless of whether you could have or did know of the malpractice.
You're going to have a challenge not only proving causation & damages, but also overcoming the statute of limitations defense, which limits the amount of time you have to bring a particular claim. It would not hurt to contact a local attorney in your area experienced in these issues.