Just from my own experience with my own son: If I had left him to live on his own his home would have been the exact same way, maybe even worse. Not because he is dirty or likes living that way but because for those as ill as your son or mine: organization is really really hard, -almost impossible for some, even simple things that we take for granted are so hard to do with any consistency. In addition the expectation that they must do these things is an additional stress that is often more than they can handle mentally and emotionally and they just freeze.
First I would strongly question your son’s doctor on the medicine regiment that your son is on. He needs to know how debilitated he actually is in his everyday life. Some doctors put their patients on a medication and so long as there is no dramatic (or life threatening) side effects they rely on the word of the patient as to how the medicine is doing. Often if the medicine is not optimal the patient cannot give an accurate or clear account of his or her experiences with it or they just say everything is fine-- so the doctor opts for no changes and nothing changes.
Someone close to the patient that knows him or her has to observe closely and then advocate on behalf of the patient in order for effective medicine changes to be made. I had fulI guardianship of my son early on so I could sit in on his appointments and be a part of his program. If I was not the guardian then I would be writing the doctor letters letting him know everything I know about my son’s behaviors and reactions to medications. The doctor can refuse to speak to a parent directly when there is no guardianship but any doctor worth his or her salt will take communication from a parent or other family member seriously.
I know this is not for everyone, and I fully understand and appreciate that fact: But what helped my son was when I was home with him 24/7 (I was on long term disability myself) and when that happened I began working with him daily on simple things, throwing stuff away properly, looking at dates on food, making food correctly and cleaning up after. Taking the trash out the same day each week. Doing laundry the same day each week. Making a predictable routine. It was re-teaching him things he had already known before he was ill. He was like a small child again in some ways. Often I could see he couldn’t keep up or was tired or unable to comply so I did what had to be done but I always went back to him doing it and now after 10+ years he is able to keep things neat and clean and do all the basics needed. He still has off days but he can do it more often than not. It never gets too bad like it would have and plus I am still here with him. I also learned with my son the more time he spends completely alone without one other person to get what I call “reality clarification” from the more I see delusional thinking creep in. With me around he can say something outlandish and I can now say “no that’s not right” and he accepts that he can trust me on it and he moves on.
It took forever to get here it seems. He has also been on a steady regiment of clozapine and depakote for a very long time and it seems to do the trick. I also understand everyone is different --not all patients respond the same to medicines and interactions with family. I just share my story for what it is worth, if it can help okay great and if it can’t then I am sorry I can’t offer better ideas. I do wish you and your son the best though, whatever that turns out to be.