Adrian Derbyshire posted pictures of Julia hooked up to drips and machines in hospital to mark what would have been her 18th birthday.
Julia was 16 when Mr Derbyshire found her body at the family home in Warrington.
He attempted CPR, but she spent five days in hospital on life support and died in December 2015.
“I can’t tell you all how I feel as I’ve gone past the line of devastation and loss,” said Mr Derbyshire, writing on Facebook.
“But this devastating story of a beautiful young woman who had given up on herself and life due to others needs to be heard.
“This will be difficult but I want you all to share this post. Awareness is the only way I know [how] to support others and after reading this they may seek help and support.”
The Paralympian fencer, who is also involved in Stop Hate UK, Brainwave and sports charities, has given talks to over 200,000 young people in schools across the country on hate and stigma.
Julia, who suffered bullying while living in America and accessed websites which promoted teenage self-harming, joined her father on much of his campaign trail before her death.
According to charity Papyrus, suicide is the biggest killer of young people under 35 in the UK.
Rates of depression and anxiety among teenagers have increased by 70 per cent in the past 25 years.
- Samaritans offer support and advice to people around the clock on 116 123