Hundreds of tow truck drivers from across the region joined the funeral procession today of Daniel J. Coady Jr., a fellow tow truck operator who was killed a week ago as he was helping a driver at a crash scene on Interstate 495 in Andover.Some of the drivers followed the flatbed carrying Coady’s casket from Conte Funeral Home to the North Andover Mall, where a sea of more tow trucks spilled onto Route 114, before ending at St.