How do I end a long term friendship with autistic childhood friend?
I have been good friends with this person since we were 7 years old, we are now 23. My relationship with them has always been pretty complicated, as they've always struggled with emotional disregulation and issues with social awareness due to their autism. I often feel like I can't express my opinions without criticism or counter arguments, that any moral value that they have (and that I don't share) gives them some sort of moral superiority over me. They often talk at me for extended periods of time, giving me little room to talk or talking over me/ignoring me, or shifting the conversation back onto themselves when I DO express myself.
The thing is, they have experienced a lot of trauma throughout their entire life, and I've been with them every step of the way. Because of their lack of social awareness and rigidity in their ways, they haven't been able to maintain many close relationships with anyone other than me. I have been with them through all of their difficulties, and I genuinely do care about them. But to be honest, I feel stuck in my relationship with them. They often overlook boundaries or get defensive when I try to assert myself.
They very recently came to visit me in the city that I live. The first 30 minutes they were here, they somehow forgot a very important bag at the train station, which they realized as soon as I had ubered us 20 minutes back to my apartment. I ubered us back, and their wallet was gone. That left me to cover all of their spending for the entirety of their trip here (they did pay me back thankfully), as well as carry their passport in my purse so they wouldn't lose it. They never helped me cook, or clean. They left my kitchen and bedroom a mess, not putting dishes away and spreading their stuff everywhere. I have a roommate who is not friends with this person. I understand that their autism can make them struggle with tidiness, but as a functional adult, I feel it's completely disrespectful to disregard our space and make it their own. Basically, I felt like I had to gentle-parent them for their entire stay with me. They live alone, go to school, and have had jobs, so it's not like they can't function in a "typical" neurological way.
All that to say, I can't do this anymore. I'm very sad to say that this relationship contributes nothing to my life, and puts an emotional load onto me that I'm no longer willing to bear. I really don't know how to go about this. They recently broke down to me about how they often feel othered by neurotypical people, and that their autism makes them a burden. They expressed that they feel anxious that they will no longer be liked if anyone spends an extended period of time with them. I worry about them and their mental health, but this is just getting to be too much for me and I feel trapped. How do I approach this conversation? Is it possible to salvage this friendship?