How can I discipline my 18 year old son?

I have 6 children, 3 currently live at home, 14 year old son, 20 year old daughter and 18 year old son.When it comes to chores, my daughter does most of it, the 14 year old still needs to be told but he does it in the end. But the 18 year old doesn’t do anything. I assign them all tasks to do, within an hour, the other two will be done, the 18 year old will still be sitting yelling “I will do it!” but after hours, the task is still not complete.The problem is, he makes majority of the mess in the house. So my other two are complaining, saying it isn’t fair that they have to clean up after him, which is true. He also makes the house smell of very strong BO/sweat, I’ve bought him lots of deodorants, he never uses them. The smell lingers even if he left the room 5 minutes ago.On top of this, I do weekly grocery shopping, within 2 days, it’s all gone. I’m not sure why he eats so much, he goes to the gym, not overweight, he doesn’t have any health issues. My two other kids complain, and my daughter ends up doing her own weekly food shopping and shares with my youngest son. So I’m really just buying a week’s worth of food for a FAMILY for one person.I’m not sure how to discipline him, it isn’t like my 14 year old where I can give him consequences like no TV or video games for not cleaning.My 18 year old is very muscular, tall man. I am very small, if I’m being honest I am scared of what he is capable of doing since his father (divorced) was very abusive. When I try to be assertive, he whines or gets up in my face and I don’t know what to do anymore.He can’t move out because he’s still in the equivalent of the last year of high school, and doesn’t have a job. This is an important year for him academically and I’d rather he completes it while living at home.TL;DR 18 year old makes the house a total mess, refuses or drags it out when asked to do chores, makes house smell like BO. Gets in my face when I try to put my foot down. via /r/Parenting https://ift.tt/2FAqNz1