In the wake of his son’s death in a Friday afternoon crash on Interstate 5, 87-year-old George Swift must plan the funeral and decide where he will next live.For 15 years, George and his 52-year-old son, Thomas, lived together in their Salmon Creek home. Thomas looked after his ailing widower father, who has asthma and pulmonary fibrosis, and walks with an oxygen tank. They became pals and often went out to dinner together.“I loved the guy,” George said.A celebration of life for Thomas Swift is slated for this afternoon.George occasionally bursts into tears, knowing he’ll attend the ceremony and visit his wife’s grave Friday morning.Thomas Swift died in a three-car collision around 4:20 p.m. on Interstate 5 south near Barbur Boulevard when his car was struck from behind by a Ford F-150 pickup driven by Ronald D. Witt, 56, of Tigard, Ore. The force of the crash pushed Thomas’ small Chevrolet coupe into an Audi it had been following. Southbound I-5 was shut down for more than three hours at the peak of the evening commute.Witt was distracted and didn’t see the line of traffic stopped in front of him, according to the Portland Police Bureau.While he tested clean for alcohol and submitted to a blood test, Witt has a history of DUII and having his license suspended or revoked, making him a habitual offender, officials said.Tuesday, he appeared in Multnomah County Court on a charge of aggravated driving while suspended, a felony. He’s due back in court at the end of August. In an interview with The Columbian’s news partner, KATU-TV, Witt said that he probably should not have been behind the wheel.