I have a copy of my mother's will and I am the executor... my brothers are asking me for a copy of the will. They are giving me a hassle about a very small estate which I have conducted as per the request of my mother's will.. am I legally obligated to provide them a copy of the will?

No, but why don't you? If it's filed for probate - I don't know your State - yes, they will receive a copy.

Are they beneficiaries? If so they are entitled.

Yes, I would assume they felt they should have gotten something, so give them a copy to show they did not get left anything in the will.

Of course if they were left something in the will, you have to give them a copy

Are they beneficiaries? If so they are entitled.

Whether they are devisees according to the will, if they are children of the decedent they have the right to review the probate court file and see what the will says.