There's a small banner hanging in her window with a gold star on a white field, trimmed with red. It identifies her as a "gold star mom," a mother who lost her son in combat.
The gold star is a way to honor her son's memory. It's the same reason she wears a black metal bracelet engraved with his name, Spc. Joseph "Joe" Lucas.
"This bracelet never comes off," Gavin said.
Her son was killed Dec. 12, 2005, when an improvised explosive device went off near his Humvee during combat operations in Balad, Iraq. She learned the news on a Thursday night when she called her daughter-in-law, Heather. She didn't answer, so Gavin called Heather's mother.
Joey's dead, Heather's mother told her.
"I freaked out and lost it," Gavin said.
Lucas was 23.
He was raised in Maine, where he loved to snowboard, ride his bike, and play football and soccer. An elementary school photo shows him wearing a cast on his wrist from a bicycle wreck.
He moved to Augusta when he was a teenager and attended Butler High School, where he earned the rank of cadet captain with the Marine Corps ROTC.
Public service was always in his heart, Gavin said. His first career choice was to be a state trooper -- he was awarded a badge posthumously.
His second career choice was the Marines, but when he couldn't pass the aptitude test, Lucas enlisted in the Army. He married his high school sweetheart in late 2002 before he was deployed to the Middle East in the buildup to the war.
During his first tour, he wrote a letter that was published in The Augusta Chronicle thanking people for the support he received back home.
"I just want to say 'hello' to all my friends and family ... and thanks to everyone else who supports their troops from Augusta," he wrote. "I couldn't have gotten through this war if it wasn't for the support of my loving wife ... I love all of you, and thanks. I'm coming home soon."
Before his second deployment in 2004, he learned he would be a father. Lucas delivered the news to Gavin in his typical casual style during a phone call, saying, "Hey, Grandma."
"I was so excited," Gavin said. "I always wanted to be a grandma."
The days after her son's death are a blur to her. Someone explained the significance of Lucas' medals to Gavin some time around the funeral. She can't remember what any of them represent, just that her son had so many.
"I thought, 'Golly, all this for Joe?'" Gavin recalled.
She is still haunted at nights by thoughts of her son's death. She was eventually prescribed medication to provide her some relief.
Holidays are the hardest time for her, and December is a double whammy because it's the month of Christmas and her son's death.
"Don't talk to me during the month of December," Gavin said.
She didn't know anything about being a gold star mom before she was introduced as such by a friend. Now she finds it a comfort to know there is a network of other mothers in her situation.
Her sadness is tempered somewhat by having her grandson, Joseph Jr. -- nicknamed L.J. -- at her apartment. He looks and acts just like his father, Gavin said.
Lucas' younger brother, Jason, joined the Marines shortly after his death. Gavin tried desperately to discourage him from enlisting, but he had a strong incentive to serve.
"I have to kick the (butt) of the people who took my brother," Gavin said he told her.