Her friends not addicted to alcohol, shes addicted to P and possibly MDMA (to poster above). MDMAs potential for physical addiction is low, so it most probably is just P. She needs to be enrolled in a rehab program as soon as possible. Custody, or even visitation rights, will not be restored until she is clean of her addiction/s. My advice would be to talk to her in person if possible, try convince her to go to a AA/NA meeting and go with her for support, or even better, enroll her in a rehab program. Unfortunately the chances of success are only as great as her willingness to accept she has a problem, and her willingness to change her ways.
Good luck