Mark van Dongen was the victim of a “truly dreadful” acid attack in September 2015 leaving him in “unbearable constant physical and psychological pain”.
The 29-year-old died at a hospital in Belgium on 2 January 2017 after deciding to end his life.
Berlinah Wallace, 49, was found guilty of throwing a corrosive substance with intent but has been acquitted of murder.
Mark’s younger brother Bartje van Dongen exclusively told ITV News: “I think that night he lost everything he can lose.”
“He was my best friend and the biggest loss I have ever made in my life.”
“If you burn you can do nothing more… lots of pain everyday…for what you want to live?”
The van Dongen family has been torn apart by Mark’s death. His father, Kees, who has been in Bristol for everyday of the trial has visibly aged.
Bartje told ITV News: “He looks 30 years older… if you look at the hands of my dad, he can’t hold them still… only shaking.”
“My father lost everything… he lost his house, his money…the same story as Mark – he lost everything.”
He says that his father now only has around £100 in his bank account and does not know what he will do next. Desperately concerned for him, Bartje has set-up a fundraising page to try and support him.
Kees told ITV News that Ms Williams is “the devil personified” but Bartje has nothing to say about the woman who attacked his brother.
“If she got life sentence I will be happy but if she got five years it doesn’t matter… Mark will never be back.”