Ask HN: Get a GED to Skip High School or Online School?

My nephew (jr in High School) has medical issues that have prevented him from attending classes, such as PE where 80% of the score is participation. Based on conversations with his School Counselor, they are recommending he do online school instead. However, he is very smart and a motivated programmer that wants to do research. I'm wondering if anyone here started with a GED and was able to get into a good state or ivy league school and/or graduate school.

If I were in his position, I would want to quit, get a GED right away, and get some online community college credits while I hone my development / research skills.

Are there any relevant experiences or thoughts you have? Much appreciated.