Warmer Bruder is part of a large group of German expressions relating temperature to homosexuality, especially male, and deserves special attention, not only because of the anachronistic expressions is the best known, but because it brings with it part of the history of what we now call homosexuality, from the Middle Ages to our days.
The first part, warmer, that you can find developed in its own entry in this dictionary, can be translated in various ways and always related as warm, affectionate, heated, friendly, etc. The second, Bruder, means brother. Thus, the expression warmer Bruder can be literally translated as warm brother, affectionate brother or heated brother, and it would be a derogatory expression to refer to homosexual men.
The first references found of this slang date from the 18th century and would be related to different maneuvers of persecution and execution, as well as judicial proceedings, against male religious congregations, to which on a well-founded basis or not, were accused of homosexual behavior and pedophilia. Examples of this would be the interested annihilation of the Order of the Templars in the Middle Ages, the judicial proceedings against religious congregations in the 18th century and the Enlightenment, and those carried out by the Nazis in the 1930s, the so-called “Processes of the convents” (Klosterprozesse). These religious men were called and are usually called brothers, so Bruder would refer, not to family bond but to priests.
Regardless of whether or not the previous processes were adjusted to reality, the relationship between the Catholic Church and pedophilia, caused in our opinion by the unnatural aberration of celibacy, is an indisputable and cutting edge fact, whose action and impunity logically is increasing the further back we go back in time. The slang warmer Bruder, therefore, could have its origin in sexuality on the part of male members of the Catholic Church that was extended to all homosexual men by the mere fact of being so. For this reason, we prefer to translate warmer Bruder as a warm priest.
Variations: Webe (abbreviation), warmer Onkel (warm dude)