Then it might be easiest to just start over from scratch and restore a backup.
You probably can’t do anything from an Android phone. You might be able to install a Linux VM on your Windows Machine using VirtualBox or the like. You could create a Live CD or USB drive and boot your Windows machine into Linux as another option.
Finally, ParagonSoft makes an EXT2 file system reader that will let Windows read the SD card, but you really need access to visudo to edit the sudoers file so I don’t recommend that approach.
You will need to research what a sudoer’s file is supposed to look like. Then copy the suoder’s file from your AIY. That will probably be enough. If not, you need to add an entry for user openhabian.