(He meant Judas, the son of Simon Iscariot, who, though one of the Twelve, was later to betray him.)
Judas has his name given in full as an indictment. John did not pass judgment on him for the enormity of his crime, but just related the facts and lets the reader make his own judgments.
Judas was chosen by Jesus to be one of His disciples, and yet He was not “chosen” to receive eternal life (John 13:18).
John 13:18 “I am not referring to all of you; I know those I have chosen. But this is to fulfill the scripture: ‘He who shares my bread has lifted up his heel against me.’
He was one of the twelve and yet he went to hell. Going to church, doing things — even great things — for God, even having a position in the church does not guarantee your salvation. The only thing that does is if you by faith receive Christ and give yourself completely to Him. His Words are words of eternal life, but they must be believed and received to give that life.