if your sister's by your server in-person, maybe you could guide them to graphically install something like Rustdesk (edit: graphical remote access, wayland isn't well supported so make sure it's running over Xorg), give you the access code & have them manually accept the connection so you can get back in.
You'll be stuck streaming your terminal window and sending laggy keystrokes though whatever connection you have now (until you can get ssh running), but it's better than nothing.
Do you have any posts/reading on the win32 additions to the kernel? I vaguely remember something similar being talked about some time ago, but I can't find anything right now.