I understand the confusion, but according to the OP they have never been the owner, this was their father.(but 'I' as opposed to 'he' does rather come across, so who's actually who?)
If as per the OP, then it's their father's circumstances during the 'in-time' period which are key.
We haven't had any info direct from the father.
We're told by the OP that they had and continue to have health problems and I have suggested that on behalf of their father they contact bailiffonline to see whether they might be able to compile a compelling OOT which fits the circumstances.
Who knows?
OP, your continued procrastination and failure to post the Notice of Enforcement is likely to mean that your father would be charged the additional £235.
Paying has NOTHING to do with which TEC form is used. Pl get on with it!
As I and others have explained in detail, the circumstances of the PCN etc. are for the moment irrelevant. You were told which grounds applied for a SD to be submitted.
This is the process in which your father is embroiled:
https://www.londontribunals.gov.uk/ruc/understanding-enforcement-process