How do I handle a long gap on my résumé? (update)

I took time out to care for a family member after working as a graphic designer. It has been weighing on me all week. I am not sure how much to explain. What do you say in interviews?

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.

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