First Timer Seeking Advice

Every autistic individual is on the spectrum, so his needs might differ from someone else's needs, so you'll likely have to get his input if you want to create a suitable space that's specific to his needs.

And also, it's kind of concerning for me to hear how his entire flat is going to be changed and rearranged on him, and what about the items that he's been hoarding? Is it just going to be all thrown away without his knowledge?

He had a psychotic episode so he's at the hospital, but did he agree to getting his flat changed? And why are you asking what designs would meet his needs, when that information should come directly from him? Because we don't know what his specific needs would be, as that's different for every autistic person. 

I just imagine a scenario, that he's at the hospital, so you're taking the time to clear out his flat and make it brand new before he returns, as a form of a surprise. I don't know if that's truly the case, but I'd say that he could either be very happy, or very upset by having his environment completely changed on him without prior notice or consent. 

I mean I only mention that, because a family member of mine who was hospitalized for a few months, and other family members and relatives decided to throw away her belongings that they thought she didn't need, she lost her old apartment without her knowledge, and they tried to put her into a new building in a new apartment.

She was so distraught once she realized all of this, she said "I lost my home... my home. I lost my favorite items. I lost everything." And she went into a great state of depression, that doctors were like "We can't help her if she's not trying to help herself," and they just left her in depression. The doctors didn't know she just lost everything of hers, and family was too ashamed to mention it to anyone. Then the family said that she might be able to get her old apartment back, and that gave her motivation to get up and to do stuff, believing that the faster she recovered, the faster she'd get to go home. But when she realized that it was all a lie, and she won't get her home back, she fell back into a deeper depression. She was grieving everything she lost that was familiar to her, her home and her belongings, and everything she knew that she couldn't get back. It was almost like she felt homeless. After she passed away (due to old age), I kept momentos that reminded me of her favourite things she lost, just to remind myself of her.

I mean I can't say for certain how your brother might react. He might like it and appreciate it, or he might just get really sad. I don't really know. But if you wanted to change his flat around, I just hope he knows about it, and that you're working with him on it so it's not a complete shock for him. 

Thank you for your input.

Yes, my brother knows exactly what’s happening. He’s asked me to clear it. It was pretty much uninhabitable in it’s previous state. 
Sometimes I bring him to the flat where he’ll see what’s going on.

It’s not easy of course but he can see and understands how necessarythis is for his general well being and long term health. I realise his needs may differ from others. 

Thanks 

Thank you for your input.

Yes, my brother knows exactly what’s happening. He’s asked me to clear it. It was pretty much uninhabitable in it’s previous state. 
Sometimes I bring him to the flat where he’ll see what’s going on.

It’s not easy of course but he can see and understands how necessarythis is for his general well being and long term health. I realise his needs may differ from others. 

Thanks 

I just thought about this, but if your brother has light sensitivity issues, to have lights that could be dimmed to different levels of brightness could be helpful. I also block out windows when there's too much light or sounds coming from outside.