In this au the death/loss of Katsuki completely affects Izuku to the point that he just goes through life day to day without any real thought, so that's why you see as if his clothes change and his environment. He's just going through the motions. Nothing is enjoyable to him anymore like when you see Uraraka chatting with him he is unresponsive and still has the same dead expression. In Uraraka's point of view maybe he seems normal but how he really is on the inside is what we're seeing here. Th