Psychedelic session for veteran - possibly for someone with multiple PTSD after military deployments?

Is a psychedelic session possible for someone with multiple PTSD after military deployments?

I am asking this for a veteran I know. He sustained various traumatic experiences during ten deployments to war zones. He has since been diagnosed with multiple PTSD. Over the past few years, he has tried many different therapies, often in combination with medication, but unfortunately without much lasting result. The symptoms he suffers from most are flashbacks, emotional dysregulation, and periods of depression.

Since conventional treatments have brought little improvement so far, we wonder whether a guided psychedelic session might offer a form of relief. The primary goal would be to better feel and process the underlying traumas, so that the flashbacks become less intense.

Regarding medication, he is currently still using a number of drugs, but this has already been significantly reduced. At present, this involves Omeprazole (stomach protection), Tamsulosine 0.4 mg per day for urinary problems, Ritalin 30 mg per day, Quetiapine 50 mg per day, and Pregabalin 300 mg per day for nerve pain. If necessary, he is willing to further reduce the medication or temporarily stop it when needed.

In terms of substance use, he currently uses cocaine approximately twice a week. In the past, in addition to cocaine, he sporadically used ecstasy and occasionally speed. Furthermore, besides PTSD, he also suffers from ADHD and problems with emotion regulation. Physically, he has nerve pain in his hands and feet, but otherwise, there are no other known physical conditions.