Is there any info on the PCN about viewing the video, (the sole evidence of the contravention) ? We need to see this to give good advice. I tried looking for it on the WF website but can't find it. Of course it's the usual useless website, of course !
Found the video, which is available on the "challenge PCN" page. You are indeed correct the stop time was only 2 seconds, which for me is de minimis and they should give way on this, but won't, so you would have to take WF to London Tribunals with the full PCN penalty in play. However, you must first submit reps to WF, get them refused, and only then can you register an appeal at London Tribunals.
I don't think mentioning your fathers mental health will help matters, but see what the others say. I assume it is your car, correct ?