He's nothing other than a thug and should be banned from any involvement from the game.
His record per Wikipedia:
"Barton's career and life have been marked by numerous controversial incidents and disciplinary problems and he has been convicted twice on charges of violence. On 20 May 2008, he was sentenced to six months' imprisonment for common assault and affray during an incident in Liverpool City Centre. Barton served 74 days of this prison term, being released on 28 July 2008. On 1 July 2008, he was also given a four-month suspended sentence after admitting assault occasioning actual bodily harm on former teammate Ousmane Dabo during a training-ground dispute on 1 May 2007. This incident effectively ended his Manchester City career. Barton has been charged with violent conduct three times by The Football Association: for the assault on Dabo, for punching Morten Gamst Pedersen in the stomach and for attacking three players on the final day of the 2011–12 season.