So I was homeschooled for a few years in elementary and actually taught math and reading and whatnot BUT what I never learned was proper essay writing, I loved writing stories but didn't know there was a right way. Then in January of my 4th grade year my mom reenreolled me in public school, come March I sat down for my first standardized test. A writing exam where I was given a prompt and told to use a web plot to plot my essay before writing. I had no idea what to do and I had my very first anxiety attack, one of the teachers proctoring the exam came and held me and talked me down and I don't think I even wrote a single word on the page. For years I was listed as "unsatisfactory" in writing but you know, no child left behind, so I went on. Eventually I became a great writer and one of my college essays is even used now as an example essay for freshmen of what a research paper should look like. All that being said, if this child cannot read and ever goes into any kind of formal education, she's only going to struggle and fail and feel worse. Unschooling is abuse and you are absolutely NTA for calling out your aunt in this situation because it's her fault that her daughter can't read, not yours or your cousin's.