More on the active chem in panacur. It can be toxic. https://en.wikipedia.org/wiki/Fenbendazole
I’d think you’d want to understand this toxicity better before getting onboard, unless you’ve had the misfortune to get a very late diagnosis of metastasized cancer with little hope otherwise, like the position in which this man found himself. The toxicity over time could be a problem. Not that big of a problem if you’re facing demise otherwise, but a big one if you’re not.