Thank you so much for your reply and your support, especially as you also went through something like this 
I’ve already filled out both the challenges & circumstances and the additional info sections (with the former focusing on how I took care of her for a majority of my ‘major’ year, and the latter focusing on how this impacted my ECs due to the school switches + losing transport methods at some points). After reading this thread, I’m also planning to include it as an EC. Would you recommend also asking my guidance counselor to include it somehow? I feel like I’m already ‘harping’ on it, although it’s important — but I don’t want this to be a situation where I’m overexplaining to the point of any suspicion or exhaustion.
Again, thank you so much!!