He may be credited with the leadership which brought changes in the practice of psychiatry after World War II and in advocating the treatment for people with mental disorders.
At age 13, he came to the United States to continue his education and worked through high school and college.
In 1972, he was awarded an LLD degree by La Salle University in Philadelphia, Pennsylvania, and an honorary Sc.D.
Through the WSA, Blain directed the provision of medical care for casualties in the Merchant Marine Service.
Blain was instrumental in providing psychiatric and neurologic care to thousands of veterans who were rehabilitating in inadequate VA hospital facilities and VA outpatient clinics which had inadequate numbers of trained medical staff.
Blain forged relationships between the newly organized National Institute of Mental Health (NIMH) of the USPHS, and with medical schools and universities.
The new relationships between the VA hospitals and clinics established training programs in psychiatry, neurology, psychology, social work, and psychiatric nursing which led to the infusion of trained professional medical staff.
Blain reorganized the Psychiatric and Neurologic Division's central office by adding trained staff who were responsible for the patients.
Blain was in the VA post for two years (1946–1948) when the American Psychiatric Association (APA) reorganized, and established the position of medical director.
He spent a year as the director of Mental Health and Research and Training of the Interstate Commission of Higher Education.
He was named Emeritus Professor of Clinical Psychiatry at the University of Pennsylvania Medical School.
From 1966 to 1970, Blain was the superintendent of Philadelphia State Hospital at Byberry which had a long history of custodial care.
In 1975, the Salmon Committee of the New York Academy of Medicine awarded him its Distinguished Service Medal.
The Study of Standards for Inpatient Care for the New York City Mental Health Board.
The Trade in Lunacy: A Study of Private Madhouses in England in the Eighteenth and Nineteenth Centuries.