What?
They cannot help unemployment by making it more expensive for businesses to operate.
That will cause even higher unemployment.
Deflation would help unemployment and NOT inflation.
Which is why the Fed is committed to keep interest rates as low as possible and is willing to accept a rise in inflation in order to do that. If it's cheaper to borrow then business can expand and add on staff. You fight inflation by cooling down expansion and you do that by raising interest rates.