multiple over the counter sedatives and alcohol

My best friend may have a serious problem. She takes A LOT of over the counter medications with sedatives; predominately Dramamine, Benadryl, and "night-time" pain relievers containing Diphenhydramine. Day and night, she will take as many as eight or ten pills at a time (always mixed combinations of the above), often with alcohol and marijuana. You can tell when she has done this even if you didn't see her, because she becomes "slow" and clumsy and accident prone and slurs her speech. My question is: apart from the risk of overdosing, what kind of long term effects might this have on a person? Can this cause brain or heart or internal organ damage? Can this create unbreakable addiction? How long can this go on before it kills her? What should she do?