Is it counted as three divorces if the husband says that he divorced his wife three times, five months after his initial statement that he divorced her while she was menstruating, and none of these divorces were documented in writing? And if he were to write them, would it be counted as one divorce or three?

If you mean documenting the divorce, know that it is effective whether documented or not. The divorce of a menstruating woman is effective according to the majority of scholars, and the husband sins by it. Shaykh al-Islam Ibn Taymiyyah, however, was of the opinion that it does not take effect.

As for the three divorces your husband informed you about: 1. If they were after the iddah (definition) ended without resumption of marital relations, they are not effective because the marital bond has ceased. 2. If they were after a resumption of marital relations, or before the iddah of the first divorce ended, then they are effective. In this case, you become unlawful to your husband until you marry another man in a valid marriage.

Shaykh al-Islam Ibn Taymiyyah's view is that three divorces uttered in a single expression count as one divorce.