Ok, I am this guy, I do exactly the same thing, i'm lazy and i'm bone idle but I love my girlfriend very much and WANT to help her, but the problem is that all my life my parents pampered me like mad, I never had to lift a finger, when I lived on my own my house would descent into a state of squalor over the course of about 3 weeks before I would think about cleaning it up.
Its now 4 years later and I've lived with my girlfriend for two years, I'm still messy but i'm not as bad... I help out if she asks and occasionally when she's out I'll Blitz the house so it is spick and span but if she doesnt ask then the chances are I'll not even notice that its being done.
If he helps you when you ask him then I'd let him be and realise that some people just are not wired to think like that... of course I work from home so if I'm not cleaning then I AM working my arse off on other things, if he's out playing with his mates whilst your slogging away then thats a bit unfair.
but just try asking him to help you and see what he says, if he says he will help when you he gets home then DONT clean up whilst he''s out (as I know you do as thats what my girlfriend always does) just leave it... when he gets in wait till he's sat down and got comfy and ask again... if he still puts its off then... well... you've seen Chigago ( or you can just kick him out)