Research of psychedelics is extremely crucial. Even more so on a first time experience with the psilocybin dosage included to counter act with the large dose of 2C-E. I could swallow psilocybin and LSD for days and end at over dosing amounts without problems. The thing is, 2Cs are much different and very potent and, considering the minute amount of research on the specific substance, you can expect one to feel things they have never experienced before or simply not be able to cope with the hallucinations and introspection.
As far as the dosage goes, 15mg is a safer first dose for 2C-E and anything other 2C for that matter. The only exception would be 2C-P, 2C-T-4, and 2C-T-7. They have a slightly lower dose requirement. Your friend needs to do a lot of research and understand more than just what one substance does and, instead, focus on the grasping, understanding, and enjoyment of a trip. I'm sure your friend had a fine time but just wasn't prepared for the effects which threw his trip off balance slightly. Although 2C-E is extremely amphetamine backed in the sense that you took a very high dose of MDMA with it. This has always proved to be the safest for not having a difficult trip on due to the roll it gives and the serotonin released.
As a final note, the mushrooms could have easily been introspectively frightening, especially when mixed with a true hallucinogen.
