Not taking the piss. Why dont you put a walk in between him and his beer to get him moving.
If he cant stop beer, can he at least eliminate soft drink?
So walking and no soft drink.
Walk to a pub 20 mins away, then to one 40 mins away. etc etc. So you dont turn his habits upside down but just make him work for it a bit. A reward for his efforts so to speak.
Maybe once he starts moving it will gather momentum. Walk with him. Anyway good luck to him.
