How do I handle a long gap on my résumé? after 12 years as a teaching assistant

I took time out to care for a family member after working as a teaching assistant. I am in San Diego, in case local advice matters. I am not sure how much to explain.

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

A short, honest line such as 'family caregiving' is enough for most employers. They mostly want to know you are ready now.