It has been a long time since anything like this has come up. I used to make a mixture of two plants to help people off of heroin and methadone cold turkey. I showed them how to make the tea and how to use it without killing themselves as well as how and where to collect the plants. Once they got the hang of it this one couple opened their house to people trying to get off the drugs as a place to stay for a couple of weeks while they learned how to make and use the tea and to get over the "hump" of withdrawal. Last I heard there were 7 people altogether that successfully got off the methadone and heroin. I don't publicly discuss what these pants are though since one is especially toxic if used improperly, which includes using the wrong part of the plant. What I am hoping to do is to someday find a drug company that will take on the production for treating drug withdrawal. They can isolate the known active components of each plant and mix them in specific quantities to increase the safety. Although when mixed the safety does increase since the tow herbs work synergistically. Each herb on their own only provides mild relief. Combined though they said the combination knocked out about 95% of their withdrawal pain.
Luckily their is another, readily available alternative. The amino acid DL-phenylalanine is a precursor for the neurotransmitter dopamine. Dopamine production is shut down by opiates leading to a number of withdrawal symptoms. Recommended dose is 1000mg 3 times daily at least 30 minutes before meals. It does take about two weeks to kick in, so she needs to be a little patient.
In addition I recommend trimethylglycine (TMG), also 1000mg 3 times daily and if she can find it the herb bupleurum. If she can find the herb let me know what form it is in so I can recommend a dosage. I have not seen capsules of this herb, so it will likely be a powder (the best) or a tincture. These can all be taken at the same time.
Sources of B vitamins, such as rice bran, are great for strengthening the nervous system. And make sure she stays hydrated with some good mineralized or silica water.