OTTAWA -- A former NDP member of Parliament says his brain cancer is terminal.

Paul Dewar, who represented Ottawa Centre from 2006 until 2015, announced in February that he was undergoing treatment for a brain tumour but did not give details of his prognosis.

Dewar now says that he was diagnosed with terminal grade 4 glioblastoma -- the same type of cancer that killed Gord Downie.

In an open letter, Dewar says the disease has given him a "new determination" to support young people's aspirations, so he and several friends have founded an organization called "Youth Action Now."

He says the organization will "support grassroots change driven by young people."

Dewar lost his seat to Environment Minister Catherine McKenna in the 2015 election, and became a board member for Human Rights Watch Canada and Partners in Health Canada.

His late mother Marion Dewar served as Ottawa's mayor from 1978 to 1985.