Principal residence or second home and council tax register in relation to the IT Nil Rate Band

[Andrew Roberts]

Hello,
My father owns a house in the countryside and rents a house in the city. The local council have just deemed his country house as a second home and doubled the council tax rate. His city rental house is with a different council and they have this address registered as his primary address.
Will the country house that he owns still count towards his 'nil rate band' for inheritance tax purposes despite current the 'second home' status or should I endeavour to change this with the local council?
Would there be a minimum time he has to live there per year to qualify?
Any help with this would be very much appreciated!
Thank you.

[pawncob]

His total assets will "count towards his nil rate band".

[AGoodman]

and it only has to be a "residence" to qualify for the residential nil rate band, not a main residence.