brother-in-law
In German, the word 'Schwager' is used to refer to a brother-in-law. It can be used to refer to the husband of one's sister, or the brother of one's spouse. The term is gender-specific, so for a sister-in-law, the term 'Schwägerin' would be used instead.
My brother-in-law is a doctor.
The German term 'Schwager' in this sentence refers to 'brother-in-law'. The complete sentence translates as 'My brother-in-law is a doctor' in English.
Your brother-in-law has invited us for dinner.
In this example, 'Schwager' is used to depict someone's marital sibling, in the context, it's 'Your brother-in-law'. The English translation of the complete sentence is 'Your brother-in-law has invited us for dinner'.
His brother-in-law works in a bank.
Here, 'Sein Schwager' is the subject of the sentence and it translates to 'His brother-in-law' in English. So, 'Sein Schwager arbeitet in einer Bank' translates as 'His brother-in-law works in a bank' in English.