No when he died they will have expected you to look through his papers and found his bank details. But you have taken money out of his account after the date of his death which is a big no no. All the dd's should have also been cancelled. If his estate is large enough to go to probate the balance at his date of death has to be taken into account for probate puposes. This is anything in his own name totalling £5,000 or more, including any jewellery or possessions and life insurance policies that will pay out, unless they have been paced in Trust.
If the estate is less than £5K the Bank can pay out funds under an indemnity. All the direct debits you still want to be paid have to have a new auithority signed by you and paid out of your personal account.