So when I suggested that she lighten up her presentation a bit with some humor, she balked. She said she felt she should be more reverent. The opposite of which is -- of course -- irreverent.
You don't need to revere your audience.
When people are dealing with heavy issues, the last thing they need is a speaker who brings them down even more, or walks on eggshells around them.
Yes, using humor when your topic is delicate takes a light hand. But I guarantee you this: Every single person who has ever survived a tough challenge has found humor in the situation. Because that's how you get through it.
Revering the topic so much that your presentation is 110% earnest and serious will just bum out your audience.
So find the humor in their situation.
If it's a situation you've experienced, even better, because you're all in it together.
If you haven't experienced their situation, there's still humor to be found.
There are two ways to use humor with difficult topics:
1) Find humor in the issue
This works better if you're "one of them." I know of several speakers who talk about things like cancer, depression and epilepsy, and they weave the humor of their own situations into the presentations. Make sure the humor is universal enough that the audience can relate to you. I particularly like Courtney A. Walsh's motto: "All Aboard the LoonyBus — You don’t have to be crazy — but it helps!"
Here's a great article about coping with infertility through humor. In the article, the author mentions the New Yorker's cartoon bank. Topics include anger, depression, psychiatry and stress. Here's a site for cancer humor. Personally, when I was experiencing debilitating panic attacks and anxiety, I probably laughed as much as I cried. Making fun of my situation was sometimes the only way I could talk about it.
2) Find humor in other areas of your presentation
In the instance where you are not someone who has experienced what your audience is going through, don't insult them by pretending to be "in" on the joke. Find other aspects of your presentation where you can add humor.
When I was speaking on domestic violence, I would ask the students how many of them had a sister. Then I would ask how many of them had an aunt. Then I would ask how many of them had a mom. They would laugh because they were caught off guard by the absurdity of the question. The humor wasn't about domestic violence; it was humor I used to warm up the room so I could talk about the tougher stuff.
I'm sure you can think of plenty of instances of using humor when discussing a difficult topic, so I would love to read your examples in the comments.
Bottom line: Your audience doesn't want to be revered. They want you to help them, not tiptoe around them. They want to be informed, educated and entertained. And you can do all three, even when your topic is sensitive.
See this blog post with additional examples of using humor with difficult topics from some of my clients' presentations.