weakened by这句意思?

weakened by这句意思?
Therequisite visit happened typically on every Saturday, when my child spirits were at their highest as it was sunny andcould be most weakened by the narrow inner part of my grandmother’s house. My mother, accustomed to the bright, spacious farmhouse that wasGrandma’s, seemed no less sensitive to the darkness. She would set her jaw andlistened when Grandma described how many small illnesses appeared as she grewolder and would check her watch—an hour being the minimum she expected herself to endure. Herbarely contained impatience and my grandmother’s disabled age radiated outaround me.
Iwould sit at the white and red metal table with the pull-out and built-insilverware drawer, cracking almonds(杏仁). This was the one good thing at Grandma’s house, the almonds,which she kept in a green glass bowl. I would lift the lid carefully and try toset it down on the metal table quietly, then attempt to crack the nuts withoutscattering the shell crumbs（碎屑）. It was not good to draw attention to myself at GrandmaCarlson’s. Sounding angry, she would call to me in her long drawl(长调). When I failed to understand her, she would reach out to me withher trembling and wrinkled hand and shout, “Here!” She would be offering someof her handmade candy, which tasted a little bitter.
本文第一段中could be most weakened by the narrow inner part of my grandmother’s house.这句怎么理解翻译? seemed no less sensitive to the darkness这句意思是“对...不敏感”吗?前文中 My mother, accustomed to the bright, spacious farmhouse后文为什么又说对黑暗不敏感?