He freaked out when his activist students occupied the college calling them 'fascists' but later took it back, and said they were ok (that's from memory). Istvan Meszaros characterises the Frankfurt School as a vehicle for American imperialism in Germany (in the Power of Ideology), and has lots scathing to say about Adorno. Arendt says Adorno suppressed Benjamin's books, hiding the manuscripts, but I think she was being a drama queen.
Peter Marcuse gives an insight into the personal culture of the Wankfurt School in his preface to volume one of the collected papers of Herbert Marcuse:
'Horkheimer lived in Scarsdale when the Institute was in New York City, and in Pacific Palisades when it was in Los Angeles, in high class enclaves of the well to do The lifestyle was formal, with servants. Children (when they were brought along at all) were expected to be quiet and inconspicuous. Members "siezt" each other, addressed each other with the formal "you", though they had worked together (and throgh termendous turmoil) for over ten years. The affairs of the Institute were not run democratically...' (preface, H Marcuse, Technology, War and Fascism, Routledge, 1998 px.)
Peter Marcuse goes on to complain that his father and Franz Neumann were desperate and got no help, and also implies that Neumann was badly treated and wanted out of the Institute. (In fact evidence is that Adorno and Horkheimer were jealous and hostile to Neumann's superb account of German Fascism, Behemoth, and sought to bury it in favour of their own metaphysical rubbish version.
-- James Heartfield The 'Death of the Subject' Explained is available at GBP11.00, plus GBP1.00 p&p from Publications, audacity.org, 8 College Close, Hackney, London, E9 6ER. Make cheques payable to 'Audacity Ltd'