He died on Friday and was 59 years old.
The Madison Holleran Foundation announced the news Saturday in a Facebook post.
"The past 6 months have been a difficult journey for Jim," the post reads.
"He was diagnosed with ulcerative colitis and ultimately had to have his colon removed. Since then, he has been in and out of rehabilitation centers trying to regain his strength and recoup his active lifestyle he was so used to."
The Madison Holleran Foundation was launched to raise suicide awareness after Madison Holleran leapt to her death in Philadelphia at 19 years old, in 2014.
James Holleran had served as the acting executive vice president of the foundation up until last month, when he stepped aside to focus on health issues.
Holleran was admitted to the hospital last week, and died peacefully at home Friday evening.
More than $50,200 had been raised on a GoFundMe launched by Jim's son-in-law Scott Bushoven, to assist Jim's wife, Stacey. The page garnered donations and condolences from supporters across the U.S.
"I donated because after reading the book "What Made Maddy Run," the Holleran family shared their heartache to help prevent tragedies in other families and help young people find resources for where to get help if in need," one person said.
"It’s incredibly selfless and I imagine difficult to relive such pain when retelling their family’s story. Anything I can give to help them in their time of need right now seems like a small token compared to them sharing their personal story and helping dozens and dozens of people (myself included) through the years."
"I struggle with anxiety and depression," another donor added.
"Since hearing Madison’s story, EVERY TIME I have a terrible day and contemplate why I remain here, I rewatch her story and it gives me hope and snaps me out of my dark hole of sadness. The way she is spoken about and her smile has stayed with me for years and I will NEVER forget her name or her purpose.
"Thank you all for sharing your family’s hardest times with strangers and inspiring countless individuals. The number of lives you all (including Jim and Madison) have saved is extraordinary."
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