Can be used when referring to having a beer.
Also may be in reference to smoking weed.
Also less urbanly used in England to describe having a cup of tea.

abbreviated form of the word brewskis, meaning beer.

One of the thousands of UK terms for tea.

The term "brew" can refer to a friend, much like brother, Man, dude and homie. This is not commonly used when referring to a person outside of their immediate presence, only when you are having a direct conversation with the person.

lancashire slang for a 'cuppa'. it can be a cup of tea or coffee.
Most liverpudlians don't understand the concept that 'brew' can mean both tea or coffee.

To brew someone means to annoy them.

This is because brewing a cup of tea let's off steam which is related to people being annoyed.

a beer.