Question about 何月

How come for 何人 and 何日 the translation in WaniKani can be “how many people?” and “how many days?”

But for 何月 it’s only “what month?” Can you use it for “how many months?” like people and days?

Just a slow lowly level 5 here. Thanks!

In general, 何 + counter = how many of counter things. The がつ reading here for 月 isn’t a counter, so it wouldn’t work, and I’ve never seen it translated as anything but “what month”. There is なんかげつ / 何ヶ月 where ヶ月 is a counter and it does mean “how many months”, but not super common.