Have you ever taken NAC (N-acetyl cysteine) supplement - try taking it daily for 2-4 weeks to see if that helps you recover; search NAC + MDMA to see anecdotal evidence, there's lots on Reddit.

People can fuck themselves up on any substance if abused, that friend may be able to undo the damage done with MDMA via Ayahuasca ceremonies - perhaps via the neurogenesis that is seen with Ayahuasca use to recreate pathways that may have been lost due to excessive MDMA use. Not a doctor.