C.,
I know where you are. It sounds like you have really good services for Medicare, so I am not going to suggest any more, you have what you have. It is actually really good that he is able to "save" it all for you, I know that sounds stupid, but it is true. He is making progress if he is able to supress his frustration until he has his safe person, that is you (I know, you would just assume take a break, but alas, we can't!) I cannot tell you how often someone has told me how delightful my oldest child is, and my response is "who in the world are you talking about, because I sure would like to meet her!"
I do have some suggestions. Stop explaining it to him. He does not get it anyway, use fewer words, active words, concrete words, and no tape recording of himself is going to work because the basic nuerolgical executive function is not in tact for him to draw conclusions like that.
Instead, tell him what to do instead of what to stop doing, easy to say, REALLY hard to do! Instead of stop screaming, say "quite voice" instead of No kicking, say "put your feet on the floor" This is a good frustrion relever for him in general, take every tiny step of things and say it while he does things. Meaning, if you want him to "go to bed" say Stand up, walk over to Mom, give Mom a kiss, give mom a hug, walk to the bath room, open the door, stand in front of the toilet, pull down your pants, pull down your underwear, use the rest room, pull up your underwear...you get the idea. Global statements are hard for them, and if they don't have to think too much when they are tired especially, you will have fewer melt downs and better success. Success breeds success. Even one small opportunity to say Great Job! while he is going to bed will help. He will want more, but give him the smallest opportunity to do so. Planning is hard, too many steps are hard, really think about the smallest possible action involved in a global task, even though going to bed seems like one task, it is really more like 50 different actions, all actions that he can do, but break it down for him. I still do this for my 18 year old if I want her to get something done without a fight. This is so typical for kids with issues.
Same with dinner. Give him actions that he can do. Break them down to the smallest part. He probably cannot delay gratefication for even a second without frustration. If he is too hungry, the work is even harder. Offer him a snack, even if it is not your habbit, it won't hurt anything if you do. Try some thing that will bring his blood sugar up and keep it steady, protien rather than sugars, so that he has the best opportunity to be successful. He will want more success. Try to avoid the things that cause the melt down, even if you have to alter how you thought you would parent your children. It is not that big a deal, you parent your kids in ways that work, and if you have a child who metls down, you can't get through to them anyway. Don't beat yourself up if you find yourself doing things you said that you would never do. Do what it takes for him to be a success, and build on it. It is perfectly OK to treat your children differently. What I say to my kids when they complain that I give our disabled children special treatment, is this "I give everyone what they need, would your rather be him, or you?" It usually nips it right then and there. Don't feel guilty.
Last, get some help for yourself. If you can swing it, see a mental health professional. This is the harders job you will ever do, and almost 100% of primary care givers will need psychiatric care too. It is nothing to be ashamed of. This is a very debilitating experience, and it is more so for Mothers because so much of our souls are wrapped up in how our children turn out. There is nothing you can do to make him any different, and yet every message you get, every though in your collective idea of what a mother is and does says that you can, and giving up is unthinkable. Come to terms with it, and learn to cope. It will take time, but you will get there. Even now (my oldest disabled child is 18) I have moments of dispair when I beat myself up for what I cannot accomplish with her, so know that how you are feeling is totally normal.
You may not get the outcome you seek for all the hard work you do, and that is difficult to accept when you see how beatifully other children turn out with less than half the effort, but you are doing everything you can, and somehow, that has to be enough. If you are lucky, your typical child will shine and you will know that joy, so cut yourself some slack and know that you are still a good mother, even if you cannot produce typical results with your hard work.
It will be OK. You are not alone.
M.