None of the examples are punctuated correctly.
A) contains a "comma splice". You can't simply join two independent clauses with a comma.
The boss, Mike, is a bully; the way that he talks to you, and the way
that he talks to his employees >>,<< it’s not right.
You must write:
The way that he talks to you, and the way that he talks to his employees is not right.
or
It's not right how the talks to you and his employees.
If you are writing dialogue, you might use an emdash:
The way that he talks to you and to his employees - it’s not right.
(B) is also an inappropriate splice, this time misusing the semicolon.
Mick, the boss, is a bully >>;<< it’s the way he talks to you, and the way
he talks to his employees: it is not right.
Instead, write:
Mick, the boss, is a bully. The way he talks to you and his employees is not right.
You must break up two independent clauses or use a connective. If you used a connective such as 'and':
The boss is a bully, and the way he talks to you and his employees is not right.
(C) is close to natural and correctly punctuated, but again the "comma splice" is present.
Sadly, Mike is a bully. The way that he talks to his employees and
you >>,<< it’s not right.
Apply the same remedy here:
The way that he talks to you and his employees is not right.
In (D):
Sadly, your boss is a bully; the way he talks to his employees, and
you, it’s not right.
Comma splice again, but also another comma that should be deleted, after "employees".
You can read more about the "comma splice" and how to avoid it here: https://www.grammarly.com/blog/comma-splice/