Help for 8 year old

Hello all, I'm looking for some help for my 8 year old son. He's had focus issues and ADHD for many years and I've recently started seeing a Bio-med functional dr who diagnosed him with lots of parasites and yeast. I did a round of Nystatin, Diflucan and Mibidiznole (sp?), and wow, the change in my son has been nothing short of remarkable. He is a new child. However, the dr still sees a higher than normal amount of yeast and parasites in his blood and now advise he take an anti-fungal/ parasite which is high is Pau D'Arco. I started him two nights ago but he is having a very bad, ADHD, bad focus reaction due to the high salicylates in it. Can someone please advise other natural herbs or supplements which truly help rid of parasites, and safe for an 8 year old.
Thank you so much!