I'd say spend more time with him mate. The heavy hand doesn't always work. Take him out doing whatever he's into...cinema, football, looking round the shops and keep him busy but don't make it look too obvious you're trying! Chat to him like mates do. Let him speak to you, to tell you things. Could be he just needs a little guidance, putting on a straight line again. Don't forget to smile and laugh when he's with you. Good luck.