Help with advice on my deceased parent and Attendance Allowance

Hi all i am new to all this and i am looking for help or advice on my deceased parent and Attendance Allowance. My father passed away 8 months ago and claimed Attendance Allowance but had spent some time in and out of hospital before he died we then filled in the once form and registered the death and thought that was it now i have received a letter from the Dwp asking for dates dad was in hospital and a lot of others forms asking for my bank details national insurance number was there a will or probate.Dad passed away with no will and no probate and very little money in the bank so we had to use that money to help towards the funeral costs and pay the rest myself. So my question is as a next of kin am i legally responsible for Dads over payment if there is any and do have to fill in the form as there is nothing in Dads account as it is closed and no will or probate.