inherited dead mom ira

inherited a ira from deceased mom put into 17mos cd  bank sent no tax papers

,my brother took $ right out bank sent tax form his tax man said totally taxable as regular income 

he paid tax on it 

I was told it was not taxble  if i take $$ out in october when it matures do i pay tax on all $ or only on $i i  take out? etc etc   thank you !!