Science(s): natural sciences only?

From Wiktionary (see Usage Notes):

Since the middle of the 20th century, in English – but not in German – the term science was normally used to indicate the natural sciences (e.g., chemistry), the social sciences (e.g., sociology), and the formal sciences (e.g., mathematics). In the 18th and 19th centuries, the term was broader and encompassed scholarly study of the humanities (e.g., grammar) and the arts (e.g., music).

---

Usage has changed over time. Science is a rather new term, from the Latin root meaning knowledge. When the term was very new, many who today we would call scientists preferred the term natural philosopher. In contemporary, common usage, science generally refers to natural science. As such, social science is not included in science, but social science is used as a separate term. The sciences appears more often in literary contexts, and is more likely to include more than simply natural sciences. It is also used to emphasize the full range of scientific fields rather than a single practice. However, the usage of science to refer to all scholarship is historic only.

The older a source, the more likely it is that the author or speaker intended to include a greater range of fields when using either science or the sciences. The shifts in usage have been gradual. Usages are not fixed, even today. When you need to be clear, use the specific term, be it "natural science", "physical science" (not the same as physics), "medical science", "social science", "climate science", "data science", or any other.

A Wikipedia article "Science" gives a more comprehensive view of the application of the term than a dictionary could.

Wikipedia Science

It has sections about "natural sciences", "social sciences" and "formal sciences", listing some fields that fall under those terms.

I suspect that that non-native speaker wasn't a linguist. (Wikipedia classes "linguistics" under "social sciences".)