I would encourage them to also look into invasive weeds. Many of them have compounds that can be isolated to treat hundreds of issues including pain. Many are used today in their raw form. There are books on invasive weeds being referred to as "Invasive Medicine" and how to process them into tinctures and capsules. Weeds are sadly very sustainable. Just one of my Henbane plants can blast out millions of seeds in its lifetime. Even after kids come to collect all the dyers woad it just comes right back.
I remember using wildcrafted feverfew to treat allergies, I was hardcore into herbalism at the time. It is effective but the side effects are worse than commercial antihistamines although my tolerance for antihistamines has gotten worse as I've gotten older, even some of the "non-drowsy" antihistamines have serious CNS effects for me.
As for pain it is a big problem that we have no really safe and effective pain relievers. My doc says I should not take acetaminophen because it messed up my liver enzymes, drugs like ibuprofen cause stomach upset, opioids are dangerously addictive, etc.
