HI Nonnie! Yes, Balinith has Aspergers Syndrome, an autism spectrum condition. It’s mentioned both in the fic, and in the notes at the end of Chapter 30. Here’s the relevant section:

Orla Longaxe paced, her great tail of wiry black hair sweeping behind her, as the booms and shudders rocked the Mountain. The noise was deafening, and though every door in the room was closed and packed tightly with cloths, it still echoed in the walls and under her feet. In her arms, her second-born son shivered and shook. His eyes were unfocused, and he was frowning and pressing close to her chest. His ears were covered with a dark woollen hat, pulled down low nearly to cover his eyes as well.

In the corner, a little puff of steam came from a great iron pot which bubbled away softly, the vaguely soothing sound meant to combat the rattling thunder of the boulders striking the mountainside over and over again.

Balin could not bear loud noises for long.

Orla tucked her son’s head closer to hers, protectively wrapping her hand over his wool-smothered ears. Balin sucked in a breath, his hands clenching and unclenching rapidly and spasmodically, and pressed his face against his mother’s neck to hide his eyes from even the very modest light that came from the fire. Her boy was cut from a different stone, as they called it: his thoughts worked in a special and singular way. Many of the greatest works of their people had been made by Dwarrows born with minds like Balin’s, their focus as determined and passionate and as single-minded as a blade. She was prouder of him than she could possibly say. Balin was fascinated by the way things worked, by nature and first causes and the pressures under the earth and the creatures that crawled upon it. He would be a great Dwarf, his mother knew.

However, there were difficulties that came hand-in-hand with these unique gifts. Balin was clumsy at times, he occasionally lost his words, he did not enjoy company other than his parents or his friends, and he could not tolerate loud noises or bright lights. The overstimulation was uncomfortable, and sometimes painful.

…

Thank you, Nonnie! I am so happy you like the story – I wish you a wonderful week as well!