hi scott is it possible to stop the charges?

Hi could someone advise me please. Im trying to sort this out for my brother. He keeps getting statements off Halifax each month for unplanned debit interest charges, its 94p each month keeps being added and its now up to £41.38 He says he cant afford to pay it and hes been ignoring the letters so thought id try and help him. any ideas what I should do.? can he close the account to stop any more charges being added? Id be grateful if anyone could advise me. many thanks sue