Alice Maitha, the widow of former Tourism minister Karisa Maitha, died at Coast General Hospital on Wednesday.
She passed away while undergoing treatment at the Intensive Care Unit.
Alice was Maitha's third wife.
The former powerful Coast politician died in 2004 while on an official trip in Germany.
Byrum Mwakaz said his mother Alice developed health complications four years ago. He did not specify the condition that she battled.
Alice's other children are Joan Mwaka and Juney Karisa - a journalist.
Activists said the widow's death has dealt a big blow to the fight for human rights which she championed during her life in politics.
Women leaders described her as brave, loving, kind and God-fearing.
Former Nominated Senator Emma Mbura said Alice was her major source of inspiration.
"She was a brave woman ... the first woman to enter the Senator race in the Coast region in 2013. That gave women a lot of courage," Mbura said.
Alice vied for Mombasa Senator on a TNA ticket but lost to former Senator Hassan Omar.
Political activist Naomi Cidi said the Coast region has lost a fearless and motivating woman.
"She was a champion of the mnazi drink alongside her late husband. She gave Coast women the dignity and pride they deserve."
However, the women leaders hit out at the region's leaders for abandoning Alice "at her hour of need."
"She was sick but no leaders came out to help her. She was in the hospital for more than two weeks but no-one went to visit her."