The sentence I've constructed is
"My boss doesn't need to tell everyone what they has to do".
It is correct to use the pronoun "they" here?
The sentence I've constructed is
"My boss doesn't need to tell everyone what they has to do".
It is correct to use the pronoun "they" here?
Your use of "they" to reflect "everyone" is correct, however your verb should also reflect this
My boss doesn't need to tell everyone what they have to do