DS not puling his fair share around the house...

[worriedmother1929]

DD17 and DS16 are both on summer holidays, DD has a part time job at a local beach cafe, DS is working with myself and DH (as DD did last year, we need help with jobs that we can't employ someone full time for, both children volunteered to do it). DD came in every day last year and worked 9-5 for nearly three months, again she chose to do that.
DD work three or four five hour shifts a week, as and when her boss needs her. DS will mooch down to work whenever he feels like it, usually 2 or 3 pm in the afternoon. DD has spent hours when she's not working cleaning the house (she has asked for us to go out to Staples this weekend for her school stuff, so I'm not sure if it's 100% to do with just wanting to help, but that's teenagers for you), and DS has done nothing. We ask him to, he ignores us and if DD asks him for help he tells her to stop being so bossy, to put it in context today DD has done two loads of washing, and drying it, loaded the dishwasher twice, steam cleaned the kitchen & bathroom floor, cleaned the bathroom, cleaned the computer room and cleaned the lounge, with vacuuming and dusting included. Myself and DH are working at least 9-5 each day so have asked both DC to help around the house a bit, just so our weekends are less stressful, but DS has done nothing. Myself and DH are starting to feel very sorry for DD (who has undertaken this work herself, we haven't forced her to), as she has a lot of summer work for her A-levels, and is also differing from an unknown allergy.
Is there any way to make DS do his fair share of the housework? Taking away his computer and phone doesn't work, he'll happily waste away his days in bed reading, or go out and take the bus to the next town and walk around. I'm really at my end point, his attitude to work, and the house work, is beginning to become more than annoying. it often takes an hour of screaming at him in the morning to even get him out of bed, and even then he'll shower for ages, take forever in getting changed, watch TV or netflix until eventually he decides it's time. It's unfair on DD, and she's beginning to notice that he's not doing anything (She's been very good about it, not mentioning it at all), and it's beginning to get on all of our nerves. Any help or tactics to get him to get off his arse and actually do something for once help us?

[timeforabrewnow]

Watching with interest...