The husband pronounced triple talaq at once — does it count as three or one?

This is a disputed issue: the majority of the four schools hold it counts as three, while Ibn Taymiyyah and some fatwa councils hold it counts as one.
The majority view (Hanafi, Maliki, Shafi'i, Hanbali) holds that the words "triple talaq" in one sitting effect three talaqs, even though doing so is sinful because it goes against the sunnah. The second view relies on the narration of Ibn Abbas that in the time of the Prophet ﷺ, Abu Bakr and early in Umar's rule, a triple talaq in one pronouncement counted as one.
In Malaysia, the Syariah Court determines the number of talaqs after hearing the evidence and examining the words and intention. Do not make your own assumptions; apply to the court for confirmation of the divorce pronouncement. See talaq guide.