I was one to hardly ever get headaches. Then 2 months ago I was hit with them hard. Having 2 siblings with brain tumors of which one of them was cancerous and has brain cancer I went in to the doctor. Cat scan shower I had pockets of air on the brain. So did MRI and everything was fine. However during this process they drew blood and when I went to the neurologist she said my magnesium level was low. She started me on a supplement 2 weeks ago and the headaches are not as bad. Doing more blood work as I had gastric bypass a year ago so checking other minerals for defieciency levels. I take 400 MG two times a day of a magnesium supplement and its helping so far. So the magnesium your friend is taking probably has helped.