On June 7, 2022, he passed away at Mission Hospital in Mission Viejo, California, due to complications from a fall at his home. He was surrounded by his wife, his two sons and their wives, and his five grandchildren when he passed.

Mahmoud received his MD degree from University of Tehran in 1956. He had a very busy and successful practice in Abadan, Iran, where he served patients in many of the areas of medicine. However, he always felt a strong need to do more for those with psychiatric illnesses. This prompted a move to London, England to study psychiatry in 1969. After four years of study, he received a Diploma of Psychological Medicine from the Royal College of Physicians of London and the Royal College of Surgeons of England in 1973 and successfully passed the Membership examination for the Royal College of Psychiatrists, London, England, in 1974. Upon his return to Iran in 1975, he started a practice in Psychiatry in Tehran and was involved in numerous initiatives with his colleagues, such as establishing the first Suicide Prevention Center in the Middle East. During his tenure, he served as a Professor of Psychiatry, training a large number of psychiatrists in Iran and authored the first Persian-language book on Psychopharmacology.

When his eldest son was accepted to graduate school in the US, Mahmoud, his wife and younger son moved to the US in 1986. After passing the Federal Licensing Examination for medicine in New York and working in that state for several years, he started work at the VA Medical Center in Milwaukee, Wisconsin, where he worked with medical students from the Medical College of Wisconsin and continued training psychiatry residents. He retired from the VA at the end 2010, after 18 years of service. He and his wife then moved to Laguna Niguel, California, to escape the cold winters of Milwaukee.

Mahmoud had a diverse set of interests beyond medicine that ranged from music, poetry, gardening, philosophy, and mysticism. These extensive hobbies kept him busy in his retirement.

Throughout his life, he relentlessly pursued the truth in any subject and had little need or interest in any material possessions. He was a kind, gentle, compassionate man that loved his fellow man and anguished where people suffered anywhere in the world. He was particularly saddened to hear of reports of food shortages and hunger in Iran in recent years.

During his life, Mahmoud helped many people with his skills as a physician, was an advisor and teacher to many. His last act of kindness was donating his body to the UCI Medical Center, Irvine, California, for the benefit of the next generation of medical students and residents.