You might want to consider trying out the HMF neuro powder, or start with HMF forte. I would talk to him about HMF forte.
I haven’t tried phytostan before, but it could be killing off some other bugs, parasites, bacteria, etc. and thus the bad symptoms. It also contains HCL which can kill these off as well. I would be more concerned about the grapefruit seed extract in it personally. You’ll likely only use phytostan for a month or so to start out.