They' is a pronoun used to refer to a group of people. It is often used in the context of a collective group, such as 'they are all here'. It can also be used to refer to an individual, such as 'they did a great job'. In this context, 'they' is referring to a group of people, and 'he is' is referring to an individual. Therefore, the phrase 'they are; he is' is referring to two different groups of people, one collective and one individual.