A man named Drew said:
"Mohammad and I are both liars."
What are each?
First we consider the case that both Drew and Mohammad are Truth Tellers. In that case we can clearly see that no question arises why either of them can state the given statement.
Next, suppose that Drew and Mohammed are both Liars then obviously Drew cannot comment what he did. Since if he does that then he will be telling the truth.
Next, if Drew is a Truth Teller and Mohammed is a Liar, even then he cannot state that since being a Truth Teller, Drew cannot lie that he himself is a Liar.
Finally we consider the case when Drew is a Liar and Mohammad is a Truth Teller. Then it is clear that Drew is lying when he says: "Mohammad and I are both Liars", since both of them are not Liars (only one of them is).
Therefore the answer is:
Mohammad is a Truth Teller and Drew is a Liar.