Grace,
It sounds to me like the strategy you need to take with your difficult child at the moment is Do To Get. What this means is, your difficult child will only get something if he does something. According to your rules and expectations.
At his age, you have an obligation to provide him with food, shelter, and the basic necessities of life. Beyond that, anything you choose to do for him is a privilege that he needs to earn by treating you with respect, following house rules, etc.
You need to provide him with food. You do not need to have bagels, cereal, english muffins, etc. Provide just the basic fare that meets nutritional standards. A loaf of bread, a jar of jam, a few apples, tinned tuna fish with mayonnaise, milk, water. Since he's not happy with the food you provide, let him prepare his own. Do not cook for him, do not clean up after him. Make him fend for himself.
You need to provide him with clothes. You do not need to provide nice things, or designer things. Clothes from the Goodwill or a consignment shop are sufficient. If he wants something other than what you provide, he can earn it, either by getting a part time job, or treating you with sufficient respect that he starts to earn back some privileges.
You need to provide him with shelter. You do not need to provide him with extras. A bed and dresser. Or, if necessary, a mattress on a bare floor and a laundry basket to store his clothes, are all that's required. Just as with the clothes, he can earn nicer things by treating you with respect and following your rules.
If he can't speak to you civilly, don't speak to him at all. The moment he starts to become abusive with you, say "Unless you can speak civilly, I am ending this conversation." And then walk away. Do not engage with him, do not give him the opportunity to hurt you.
Keep in mind that your younger boy is suffering from all this too. Even if he's not a direct target of your difficult child's outbursts, he has to witness his mother being treated appallingly by his own brother. This can cause a lot of problems such as:
- your easy child coming to believe that it's okay to treat you or other women the way that his brother is treating you
- your easy child developing significant anger toward his brother for treating you this way
- your easy child getting anxiety symptoms, etc.
Just because your difficult child is your child does NOT mean that you have to put up with behaviour from him that you would curtail in anyone else.
I've been down this road with my difficult child. It's not easy, it's not pretty, and it may result in him escalating his anger toward you. If you choose to do this, you need to stand your ground, so be sure that you have lots of support in place for yourself and your easy child.
Sorry that you're having to deal with this. It's no fun at all...
Trinity