He died on Wednesday of terminal brain cancer, having told fans in October 2020 he had an inoperable tumour.
“Tom was a fantastic spokesperson, and he chose to bring attention to the lack of funding,” National Brain Appeal boss Theresa Dauncey told BBC Breakfast.
“He was amazing, honest and positive.”
Ms Dauncey said Parker drew attention to “solutions and treatments over the over his illness”, saying “so many people would have just shut the doors, locked everyone out and wanted to just stick with their family and friends”.
Instead, the singer “got people together, made a documentary, had a concert [and] brought so many people’s attention to this sort of terrible lack of awareness”.
Ms Dauncey said it was “incredible that he was so public about his illness, and that he was happy to share his journey”.
The singer had said he did not want to talk about “fighting or battling with cancer”, but the charity chief executive added: “But in a way, he was because he was, you know, he was shouting about it.
“And I think there must be so many people who had never thought about it before.”
Susan Short, professor of clinical oncology and neuro-oncology at the University of Leeds, said Parker’s medical condition was “challenging to deal with, even more so when you’re in the public eye”.
“It must be very difficult to know how to handle that but he did an amazing job,” she told BBC Radio 5 Live.
“It is important that individuals like him help us raise the profile of this disease and let the public know that there are these tumours that are still very challenging to treat.”
She said in terms of fundraising for “vital” research, the goal was to “try and move the field on an improved the output of these patients”.
“Tom and the band did that,” she said.
Parker had been diagnosed with an aggressive grade four tumour known as a glioblastoma
More than 12,000 people are diagnosed with brain tumours in the UK every year, and around a quarter are glioblastomas
Daniel Buck is a teacher and a senior visiting fellow at the Fordham Institute. His writing can be found at Time Plus News, City Journal, and Quillette.