Some evidence with regard to the reality of Don Juan's Story

I'd just like to point right away that yes, I've read stainless_steel_rat1's post but that doesn't mean that argument on credibility should cease. It just means that perhaps it isn't the most important question, although an important question none-the-less. I'm not going to give a conclusion on what I believe, honestly I'm not sure. I'm just going to put forth a point, to facilitate further discussion. Before we begin, it must be said that the idea that the medication 'cured' Don Juan is ridiculous.

Anyone who has experience with psychiatry can tell you that when treating a patient, one starts off with very small dosages that are sure to have no effect whatsoever, and then the dosages are gradually increased, so as not to cause harm to the patient. So no patient can be cured of such delusions with medication in a single day, 3 months of careful dosing is closer to the mark, and that is if the doctor picked the right medication, which isn't always the case.

So if we ignore that idea we are faced with the far more plausible idea that Don Juan wasn't deluded and merely choose to live in his fantasy, which is supported by much of the dialogue between him and the doctor, OR the fantasy is in fact reality. These aren't the only two options, perhaps reality is a blend of both, but I think it best to focus on these two options for now.

Notice how Don Juan said, in his final story, that he cannot lie. If this is true, and if he considers the idea of telling a false story equivalent to telling a false number of women he has slept with then this fact very much supports the idea that his fantasy is in fact fantasy. Rephrased it looks like this:

IF Don Juan's story is true THEN he cannot lie.
BUT he tells two different stories THEN he must have lied in one instance.
THEREFORE he has told a lie and so his story cannot be true, or at least his story has been proved to be not credible on at least one account.

Now, this does not guarantee that Don Juan's fantasy is not, on the whole credible. But if we are to assume that Don Juan would equate a story and a number of women slept with, then it does show that he is not a completely reliable narrator.