Former Bruins player and coach Mike Milbury won't face criminal charges for a confrontation he had with a 12-year-old boy after a youth hockey game, a spokesman for Milbury said. The spokesman made the announcement after a closed-door hearing Friday in Brookline District Court, where police and witnesses appeared before a court official. Police had sought to have Milbury charged with assault and battery, making threats and disorderly conduct. They said he grabbed, shook and threatened a boy who was fighting with his 12-year-old son on Dec. 9.