Tax refund for deceased person

My father died at the end of last year. My husband is the executor of his estate and he completed the tell us once form. A tax refund is due as my dad paid too much tax, died before the end of tax year. Will HMRC automatically refund the tax or do we have to do a tax return. How long should we wait to hear? Have tried calling but lines are busy. Any advice would be appreciated.

Hi Lynn,
You will most likely receive the refund shortly, though this can depend on whether anything else regarding your father's record needs to be finalised. For us to confirm this and the progress of the refund, you can contact us by webchat here:
Income Tax: general enquiries
Just click 'ask hmrc online'
Thank you.