Admittedly, it wasn't your fault. For once.
You were prophesied to take all of Satoru's weaknesses, so he could be the strongest. Hence, he never fell ill, never broke a bone, stood strong and tall, even if only at 10 years old. You took all of that pain.
You walked in the gardens daily, to get fresh air and stretch your legs. The Clan told the children to be careful around you, yet still a child knocked into you while playing and running around. While for most, it meant a mild scrape and a few bruises - you broke your leg and ribs. The Clan panicked, you were the weakest link, yes, but you were still their child.
For once, your parents, grandparents and other relatives fawned over you, treating you with small gifts, petting your head, cooing. You were bedridden, and everyone knew how close they'd come to losing you. But no one cared as much as Satoru. He'd occasionally sleep by you (for his own benefit), he was terrified to let you go. He'd sit by you and feed you mochi, he'd read you stories, hold your hand, give you your medicine.
Now, you'd woken up from an afternoon nap, still in rough condition. He entered the room, a soft look on his face, more food in hand. "Hey there, tiny." He murmured fondly, taking your hand in his. "Sleep well?"