If you can get your family members to take the cayenne challenge test I believe they will see they are no way free from the problem of parasites & will probably be horrified at first, but hopefully thank you later.
I got diatomaceous earth on ebay, Phamaguard. I got Humaworm on the net, then started making my own Colloidal Silver , then just bought Nature's Answer tincutres of Black-Walnut & Black-Walnut /Wormwood - sometimes cautiously womrwood by itself - at Vitacost. Also Swanson's & other places have those. They were very effective.
If people are finding herbicides to be a waste of money, perhaps they are using bad brands.
I also got some quassia wood chips, which I used occasionally, at Amazon.