I've given this some thought as to how best I can help. I feel it would be best for him to have a consult with, and receive treatment from a specialist in functional medicine if you are able to find one. It is very unfortunate that you had the bad experience with lead toxicity. Modern manufacturing guidelines for ayurvedic medicines are quite stringent and this problem is less common these days and products are labelled for safety. As a treatment strategy Ayurveda is probably best equipped to deal with this from a natural medicine perspective. However it is crucial to find an expert who has experience in managing this and ideally in a centre with allopathic medicine back-up given his current medications. If possible I would suggest you connect with Dr. L. Mahadevan at Sri Sarada Ayurveda in Derisanamcope near Nagercoil. An excellent authentic traditional Ayurveda hospital and he is a world renowned Professor. I am happy to introduce you to him if you like. In the meantime I would also suggest you study this course on auto-immune disease by Dr. Akil Palanisamy. Invaluable resources which could help you get started on a suitable diet protocol among other strategies. Hope this helps and I am happy to liase as needed. Wish you the best. https://products.theayurvedaexperience.com/pages/ayurveda-and-autoimmune-sm