I have no idea if this guy believed in God, but if he did and had faith, he is saved. God is not going to send him to hell. I used to think people who committed suicide was a one way ticket to hell. No more. God knows what is in our hearts.
The Bible does command us not to murder, and that includes ourselves. But it is not an unpardonable sin.
Not if you end your life contrary to God. Does not mean eternal damnation; remember the judgment is for when the resurrection happens.
Jesus plainly says he who endures to the end is saved. And Hebrews 10 warns against willful sin after receiving the knowledge of the truth.