One of my friends get pregnancy rash all over her body from face to toe. Right now she is 6 months old. How should I give her advice?

Your friend is a 6 month old baby? I hope you meant 6 months along. :) Pregnancy rash is known as PUPPP (pruritic urticarial papules and plagues of pregnancy). Unfortunately, there is no known cause or cure, but the good news is that it will likely subside after delivery. You can get her some emollients to ease the itch. Oatmeal based creams, cool compresses and aloe vera may help to soothe her itch. http://pregnant.sg/articles/pregnancy-rash-puppp-rash/