Indemnity form for signing

[Guest]

Hi, my dad recently passed away and he was a council tenant. I have received 2 indemnity forms from the council asking for me to sign, these are for his rent and council tax. I have been advised that dad had overpaid for both, but I don't know why I have to sign these forms and why the council have not requested my details for the overpayments to be returned. Or am I not entitled to these overpayments?*