How do I handle a long gap on my résumé? - what worked for you?

I took time out to care for a family member after working as a retail manager. This is my first time dealing with any of this. I am nervous about being filtered out. What do you say in interviews?

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

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.