My son had a similiar problem. We started him on a mild laxative MiraLAX. It is a powder we added to 4oz of orange juice (or any other drink you prefer) every morning. What it does is basically adds water to your intestines to help pass things along. Same theory as Citracel however Citracel is a fiber. I would speak to your doctor before beginning this, as I am no doctor. However, it is now an over the counter powder.
In addition to that, we watched Once Upon A Potty dvd and read books. We also had a bucket of toys (I bought him from the dollar store: matchbox cars, cards, remote control anything). When he went poopy on the potty he received a present out of the bucket. We also had a reward sticker chart in another bathroom. It all worked great. He was potty trained in less than a week.
Good luck to your friend!!