U.S. Army Reserves Staff Sgt. Rubiel Cadavid steps off the bus Oct. 8 at the Lone Star Executive Airport in Conroe, Tex., after returning home from a one-year deployment in Iraq as part of Operation New Dawn. (Eric S. Swist/AP)

President Obama’s announcement Friday of the withdrawal of nearly all troops from Iraq by Dec. 31 and an end to the U.S. war in Iraq marks a bittersweet moment for many of the families of the more than 4,400 American service members who lost their lives in the conflict.

The organization Tragedy Assistance Program for Survivors predicted that the next several months will prove “emotionally challenging” to family members, bringing back painful memories for many. “The final withdrawal of troops from Iraq drives home the finality of death to a family,” TAPS said in a statement Friday.

“It’s not over for us in December,” said spokeswoman Ami Neiberger-Miller, whose brother, Army Spec. Christopher Neiberger, was killed in Baghdad in 2007.

The organization estimates that 2,465 people lost their spouses and that 3,137 children lost a parent. Some 8,964 parents lost a child, 13,446 lost a grandchild, and 3,675 lost a brother or sister, the organization estimates. “There are a lot of people who have been impacted by Iraq,” Neiberger-Miller said.

“The impact of loss is long-term,” she added. “It’s not something they just get over.” She said that TAPS, which helps relatives of U.S. service members who have died, expects an increase in calls in coming months.

Paul Rieckhoff, executive director of the Iraq and Afghanistan Veterans of America, called the announcement “an especially poignant time for the veteran community. Many of us gave a large part of our lives, and some gave all.” Rieckhoff added that the veterans and their families “need more than just a pat on the back” and require help in tackling high levels of unemployment, suicide and mental health problems.

Sen. Patty Murray (D-Wash.), chairman of the Senate Veterans’ Affairs Committee, called the announcement “a bittersweet milestone in a war that has cost our nation dearly.”

“In nine years of conflict, our troops and their families have done everything we’ve asked of them and more,” Murray added. “Now, more than ever, it’s time to ensure that we are keeping up our end of the promise to provide the health care, benefits and opportunities our service members deserve as they return from the battlefields of Iraq.”