Natural Treatment for Adults with ADHD?

My brother is in his 30’s and severely ADHD. He has all of the hallmark symptoms and has since childhood and as many adults who deal with severe ADHD he battles cocaine and amphetamine addiction. Has anyone had successful experience with herbal remedies for adult ADHD?
Prayer has definitely helped us deal with this situation. Thank you for the kind advice. My brother has spoken with doctors before about his condition and is dealing with his addiction issues, but he doesn’t want to take a prescription for his ADHD treatments tend to be amphetamines (which he abuses). I’m just looking for a list of herbs that might be helpful and non harmful, such as St. John’s Wort, etc. I’ve been searching and everyone mentions that oils and herbs can help, but no one mentions specific ones. Thanks!