Well, congratulations for posting here. This a great site, that can help not only hoarders but family members of hoarders. There is an online support group(link to the right of the page), Sunday nights, that may be very helpful to you. We meet, and also pop in during other times. This may be helpful to get some insight or just vent. There are also some books that may be helpful, I believe, it's called "Digging out", for family members to read.
Your post has struck a personal note for me. I am sorry your brother suffers from the awful, awful disease of Schizophrenia. My father who just passed away at 63, unexpectedly, last July, was paranoid Schizophrenic. It's a life long battle, it may have been present before his traumatic events, it may not. It typically surfaces during the late teen years. For my father, we'll never know, as he was enlisted to Vietnam during those years.
These are two different issues that he is struggling with. I personally think the first area to start is his mental health, as he would struggle with hoarding anyway (his hoarding is not caused by his disease)but his mental health state can aggravate the hoarding. He has to become stable through trial and error medications. Which from my experience is a very long process, and some of which even if he was compliant, would have to be adjusted, switched, etc. There are injectable psych. meds that help stablize, there are monthly, weekly, etc. My father was non-compliant always. If he is a danger to himself or others, then he can be put into care that will help him. You must find a good Dr. that will help with the process.
This also is my opinion, but I think you need to tell him his son died. The reason you're not, I understand, however, he needs to know. If you are able to get him into care, and he starts to progress, and then you tell him, it can set him backwards, and he will lose his progress. It sounds as if he's already at ground zero currently,and if you tell him now, it may propel the care he needs to have for his safety.
The hoarding and clutter, the bringing things into the home, those are safety mechanisms. He suffered a traumatic event, maybe a few, and often those of us who have, try to overcompensate by surrounding ourselves with materials, instead of people or in addition...Hoarding is a complicated issue. I don't even know all the reasons behind my own, but I know that for me, who is in ok mental health, and others, who tend to be reasonable in other areas of their life, find hoarding to be overwhelming, and depressing. Often I can be protective of my things, not wanting others to help or touch. It makes me feel violated. Sometimes, we can be unrational. Your brother will never, ever be able to make sense of his hoarding, and be able to move forward by himself or with help from others, until his disease of Schizophrenia is addressed and starting to move forward. Hearing voices, seeing things, having the tv talk to you and tell you things, being irrational will not go away. Please find someone that will help him with this lifelong struggle. Hugs to you Arron. Please pop in to group also, for real-time support any time you need it! <3