i have doubts that he wanted to feed on purpose but the way he played by going alone vs a slark who apparently knew most of the times where to go is suspicious.
kroki2 !ban 2 days for game ruin/intentional feed + warn
like i said, i have some doubts it was intentional but because of his game the whole team lost so this will be a warning for him. next time when he sees he can't handle alone, stick with the rest of the team.