My 73 Year Old Husband Stopped Drinking Caffeine Less Than

My 73 year old husband stopped drinking caffeine less than a year ago. He had his latest colonoscopy last week and for the first time pre-cancer cells were found. Since he takes so many prescription meds, I'm having difficulty finding herbs I can give him to help. He takes blood pressure, diabetes and heart meds. I've asked him to drink at least one cup of coffee in the morning, but cucumin, flor-essence, etc are out of the question because of drug interactions. Do you know of any herbs or other more natural things he could take to help?