No doubt, colonics and Liver Cleansing would help to deal with the root cause of her acne. There is a lot of helpful information about all types of cleansing programs on the curezone site.
Also, there are two products previously mentioned in this forum that might help: 1) www.zenmed.com (haven't tried this but others here have found it works) 2) www.no-acne.com (this is an inexpensive facial/body wash that I've been using for about 10 days. I have seen a difference and think your sister might also. It carries a lifetime guarantee and if it's not effective, they'll refund your money including the cost of shipping).