Logan, 17, dreamed of going to college, marrying and having children of his own. Family and friends meant the world to him. He reveled in their warmth and in return let them know how much they were loved.
Those closest to him did everything they could to help as he battled brain cancer, including holding fundraisers to help pay for his mounting medical bills. Members of the community prayed for him and were generous to him.
Logan's fight ended Saturday when he died at Children's Hospital in Pittsburgh.
The son of William Seifert and Robin Rowe-Seifert of Haverhill, Logan was a cheery, freckle-faced teen with a smile that would light up a room.
He neither whimpered nor complained despite the pain caused by the cancer in his brain that doctors first diagnosed in November 2004. It was a rare and difficult form of cancer to treat, with slim odds of survival for its victims.
Yet Logan refused to give up.
His closest friends had nicknames for him, like "little Seif," which is how they distinguished him from his older brother Tyler, 18. He also had a younger brother, Murphy, 15, who looked up to him.
Logan was the kind of teen who was happy just playing basketball in his friends' driveways. He excelled in track events when a student at Nettle Middle School. His friends say he could run like the wind.
"I can't even explain how much I'm going to miss him," Tyler Seifert said. "He always made me smile and would make jokes and funny faces. He was a straight-up comedian. Kids liked hanging out with him because he made them laugh."
Logan's mother pursued every form of traditional and then alternative treatment that might help, and Logan bravely went along - hopeful that a cure was coming. Those treatments took him to hospitals and clinics in Massachusetts, Texas, California and Pennsylvania - where he spent the last six weeks of his life.
Logan informed those back home of his progress by posting messages on a Web site.
"I'd tell Logan that I found this treatment, and how do you feel about it?" his mother said. "He'd ask all about it, knowing deep down that the doctors did not hold any promise for his survival. He wanted to go to college, get married, have children. He wasn't going to let go of that hope."