I agree. This is an interesting idea. I like it a lot.

As Richiev and dpg suggested, perhaps the son could be the protagonist. It also addresses the points raised by Nir Shelter ?about ?the premise and ‘what’s the point?’

When the audience goes on the journey through the son’s POV we ?learn:

1. why he’s decided to help his father. Perhaps the son wouldn’t be where he is now if it weren’t for his father. Maybe a sense of guilt?
2. how important it is for the father to maintain his reputation and win this case. ?Knowing his father is unwell and he has little time before his dementia worsens and he becomes completely incapacitated, winning the case is a way to make amends as well as having his father retire from law on a reputation high
2. understand why father and son are estranged (maybe it was the son’s fault and this is why the son is doing this for his father, it’s an attempt to reconcile.

Alternatively, during the murder trial, and over the course?of the film, the audience see both POV’s of the father’s and the son in relation to their father/ son relationship and how they became estranged – maybe there are some plot twists and “I didn’t see that coming” moments and the audience question the motives for both father and son – all this set against a backdrop of murder trial which thematically mirrors the story of the main characters.

In the?TV series Broadchurch, there was a?barrister who was losing her vision (which no one knows about) and her colleague/solicitor reads and records legal documents which she listens to before she faces the court. Your story reminds me a little of this dynamic. While the barrister in Broadchurch was not the main character, it created this race against time feeling as you see the deterioration?of her eyesight?which forces her to confess that her vision is impaired.