In a statement, her foundation wrote, "Through Barbara Sinatra's efforts, more than 20,000 children through age 18 have received beneficial therapy at [the center], making it possible for them to cope with traumas associated with abuse".
Barbara and Frank Sinatra were Wednesday on July 11, 1976, and they remained married until Frank's death on May 14, 1998.
She met the singer through her previous husband, Zeppo Marx of the famous Marx Brothers comedy team.
He was previously married to Nancy Barbato from 1939 to 1950, Ava Gardner from 1951 to 1953, Mia Farrow from 1966 to 1968 and he married Barbara eight years later.
"Barbara started raising funds for it in 1985 with Frank's support", director John Thoresen revealed.
Barbara and Frank founded together the Barbara Sinatra Children's Charity Centrer in Rancho Mirage, California, in 1986.
"Frank would come over and sit and read to the kids", Mr Thoresen said of the sometimes volatile entertainer.
"A very wise French lady once said to me: 'You never worry about old flames".
She remained active at the centre until recently, pushing for creation of the video programme just past year and making sure the children had anything they needed, Mr Thoresen said.
Cowboys agree to 2-year extension with RT La'el Collins
To put that in perspective, the 20th overall pick from the 2015 NFL Draft ended up signing a four-year deal worth $9.4 million. Not only is he going up against some the NFL's best defensive players, but he'll be doing it while making a position switch.
Russia, EU Voice Concern About Proposed US Sanctions
Senate and House of Representatives reached agreement on the legislation last week, and the House could vote on it on July 26. The vote on the new U.S. draft bill is scheduled for Tuesday in the House of Representatives.