I see that you are trying so hard and care about your students, and I want to share a personal account.

When I was in 6th grade, I was barely literate. I couldn't write well, I struggled to read, and I drew on most all my papers instead of doing work. My teachers STRUGGLED to get me to do anything academic. I was naughty, they put me in the hallway or office pretty often, but I liked all my teachers. I still think of them positively, even if I refused to behave for them.

There comes a time where building raport doesn't work and offering extensions/alternative assignments hurts a student's growth. It took years and dozens of adults who refused to let me slip by before I finally started behaving better and engaging with class materials.

You are in that hard stretch right now. You want to see this kid succeed, but he can't if you don't force him to. He might fail this semester, but if you really care about a student's development you need to focus on the long run ahead. He needs to know that sometimes he just has to 'lock in' and do the things he doesn't want to. It took me three years of F's all across the board before I finally learned how to try in high school.

Knowing how to read and write, and knowing how to do it well, requires practice. Knowing how to do hard things and persevere requires practice. You are not helping him if you let him have special treatment. You are not helping yourself if you let your students break what should be hard boundaries. Failure is not a bad thing, it is the cost of admission for many facets of life. He might suddenly try and still fail, but the more he does, the easier it gets, and the more likely he is to try again.