Interesting question. I have never heard Dr. Peat reflect on this. As a Mu opioid agonist, I would expect it would be in the non-restorative category. My impression over the years is that Dr. Peat associates opioid agents and effects more with decline than restoration.
That said, Immodium is usually used in short term situations of considerable distress. Loperamide is hazardous in certain situations, including some GI infections. It seems reasonable in situations to solve urgent problems with effective methods. Generative choices are preferable in the long term.
"Endorphins: Stress induced, laterally specific, involved in estrogen action, antagonized by naloxone and similar anti-opiate drugs. I have proposed that the endorphins can cause or sustain some of the symptoms of aging. Naloxone appears to be a useful treatment for senility. E. Roberts, Ann. N. Y. Acad. Sci. 396, 165, 1982; B. Reisberg, et al., N. Engl. J. Med. 308, 721, 1983."
Ray Peat has written that all opioid agonists strongly increase histamine production. When used in cancer patients the opioid agonists contribute to the decline in health. Maybe taken with together with naltrexone would be less harmful.