I don't know if you can help but I'm looking for a fanfic where Harry was heavily abused since he was younger, and he was at Hogwarts (he was older).
Harry had gotten cursed or something and was taken back in time to when he was younger (but he wasn't there, he was just watching). Harry was put in the infirmary and if anyone touched him they would be traveled back with him and also witness it.
I think Sirius, Draco, Snape and others were also there. They had seen Harry's life since he was maybe like three, and witnessed his entire life as it kept jumping to different moments in his life.