I am very angry about it so I should imagine they are also.
It was on TV this morning that the film has imágenes of Diana's body and I know that if that was my mum, who I am very protective of, I would go (sorry about this --->) ape shit! Nobody wants to see ANYBODY they amor like that and after getting married and finally finding perfect happiness, I believe that it would hurt William and Harry even more.
The problem is is that people DO NOT consider other people's feelings when they create something like this. They could have made this a very civilised and respectful program about this topic and they decided to make it they way they did. Luckily it isnt being shown in the UK, so maybe a lot of hurt and anger will be spared. Unfotunatly we cannot prevent it being shown on YT and other websites.
But people have the option to watch it o not, but I most certainly will not.
I do think that Princess Diana's sons Princes William and Harry as well as her family will indeed express outrage at the film about her death. William and Harry will claim that this film is ruining their mother's memory in the hearts of everyone who loved her. They will want anyone who loved Princess Diana to boycott this film.