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

My résumé shows a gap from a layoff and some health issues. There are 15 people counting on me, so I am trying to be careful. I am not sure how much to explain. 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.

I was hired after a 8-month gap. The manager said the skills test mattered more than the dates.