4-month résumé gap, advice? - 15 weeks in

I took time out to care for a family member after working as a teaching assistant. I am not sure how much to explain. What do you say in interviews?

I was hired after a 4-month gap. The manager said the skills test mattered more than the dates.

I listed the volunteering and course under the same dates and kept the explanation to a sentence in the cover letter.