If she can’t get some professional advice. I’d say:
Start with microdosing daily, do it for a few weeks, see if it helps anything.
If that doesn’t help, try a macro dose (start low, maybe 1g), once every 7-14 days and see if there’s any results, while continuing the micro dose.
If that still does nothing, then increase the macro dose size (probably not frequency), to a “strong” dose (2-4g).
During all of this keep a detailed journal; self reflection and careful mindfulness is often just as important to a therapy than the medium of therapy itself.
Also, if she starts feeling some aspects of “depersonalization” or “derealization” or a sense of mental or physical detachment. I’d discontinue the therapy. Long term frequent pyschadelic use has its own sets of issues.
Are the withdrawal symptoms primarily physical? Or are there strong mental aspects to it as well? There should be some trained therapists in SF who work with psychedelics. Her local MAPS chapter might be of assistance.