They see significant self-reported pain reduction in about 30% of the patients vs 20% for placebo.

That's not how I read the abstract. It's not % of patients, but % of pain reduction, whatever that means. I assume they're referring to some self reported numeric pain scale.

The percentage of responders for "significant pain reduction" was 32% naltrexone vs 11% placebo , which strikes me as significant. If I had serious pain, and someone offered me a "widely available, inexpensive, safe, and well-tolerated" treatment with a 30% chance of "significant pain reduction" I'd be all over it. Your mileage may vary.

To sum up, there is zero reason to try it specifically, except maybe as one of the many random things to try in desperation.

Really? "Zero reason"? So you predict equal efficacy as a random treatment, such as spinning around and squawking like a chicken?

Plenty of reasons. You don't have to like them or know of them. I wasn't attempting or claiming to prove anything, just trying to point you to some information I thought would be helpful. I hope she finds something.