How to make up for past low grades?

Hi, it's always a bummer to read that someone's transcript fell short due to illness. I hope you are now healthy, positive, and motivated to make up for lost ground. Here's my honest take on your situation. I would not attend adult high school if you can graduate. Do whatever you can to graduate HS and then move on. The first thing you want to do after getting your HS diploma is to enroll in your local community college with the goal of getting your AA Associates. Since you are doing this in order to be a viable exceptional transfer student you want to be very precise about what classes you take in community college because you want it to mimic the course rigor to the top elite college applicants. Therefore before you apply as a transfer take 2 years of English, as similar as possible to the coursework covered in AP Lang and AP Lit. then take 2 years of Math, like College Algebra, Pre-Calc or AP Calc A/B, B/C, 2 years of history, US History, European History, 2 years of Language of your choice, and 2 Core Sciences similar to AP Biology, AP Physics, or AP Chemistry. That's a tall order because that's like 60 credits already and you want to get As in them not Bs. During your 2nd year of CC you are going to apply as a transfer so you also need to go down the checklist of things you need to complete to qualify. If you have 4.0 in these core classes, you will be a strong candidate at an elite college as a transfer student. Your HS Transcript will disappear and not factor in the acceptance decision. It's like a 2nd chance with a clean slate. I wish you all the best.