A rupture in the relationship of two brothers is quite apparent.

break : separate into pieces as a result of a blow, shock, or strain.
damage : physical harm that impairs the value, usefulness, or normal function of something.
breach : an act of breaking or failing to observe a law, agreement, or code of conduct.
gap : a break or hole in an object or between two objects.
rupture : (especially of a pipe or container, or bodily part such as an organ or membrane) break or burst suddenly.


Synonym of rupture is break