Thank you for your question. While we strive to provide quality, relevant information, we aren't medical professionals and so can't really address problems related to supplements used for health purposes.
That said, if you can find out from your brother the name of the herb/plant, the National Center for Complementary and Integrative Health at the National Institutes of Health provides extensive resources related to herbs/supplements and their use for health purposes: https://nccih.nih.gov/
Thanks for that Andrew. Thought it looked vaguely familiar. So followed my nose and it has been confirmed by those in Thailand as