The remarks by the son of renowned evangelist Billy Graham come before Barbara Bush is due to speak at a fundraising event for Planned Parenthood on Wednesday.
Planned Parenthood offers a range of information and services including abortion, birth control and the morning after pill.
Writing on Facebook, Mr Graham - the president of the Billy Graham Evangelistic Association - said: "Planned Parenthood is the #1 abortion provider in the United States.
"Raising funds for this organization is like raising money to fund a Nazi death camp — like Auschwitz, except for innocent babies in their mother's wombs!"
Barbara Bush, 35, is the co-founder of Global Health Corps, which promotes equal access to healthcare around the world.
In an interview with the New York Times last summer, Bush expressed her support for Planned Parenthood, saying: "So many young people want to work on social change. They want to do good.
"Global Health started because this great talent pipeline was not moving into health care. It's hard to know how you fit in if you're not a doctor or nurse.
"If we can demystify that and create channels into Planned Parenthood and other exceptional organizations, then we'll have an army of people working to solve health problems."
The daughter of former President George W. Bush is expected to deliver a keynote speech at the 2017 Fort Worth Annual Luncheon in Texas.
President of Planned Parenthood Cecile Richards told BuzzFeed News it is "really exciting" to welcome Bush to the event, adding: "It's huge, and such a diverse crowd, a lot of elected officials, a lot of Republican sort of first families."