My son just completed middle school. He has ADHD and ASD with anxiety also (my son also has severe executive function deficits and dysgraphia, making school even more challenging). We do not push grades at all. For us, it just increases anxiety to a breaking point. We have battled school avoidance and refusal for 4 years now, so we focus on getting him to school willingly, making him as comfortable as possible while there (or else he won’t go), and doing his best work. If he brings home a low grade on a test or assignment, we do discuss what he might do differently next time to get his grade up to where he’d like it to be, but we don’t admonish the grade. He does get upset by Ds on his report card (we’ve had a few over the years), but that doesn’t translate to motivation in the moment, when he needs to do schoolwork or study — they’re just too far apart to feel causal for him.
So, all that to say, grades aren’t everything. A child’s self-esteem (and actually going to school at all) are much more important. I wouldn’t put the extra pressure on grades.
Here are a couple great articles on success during the middle school years:
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism