That guy deserved worse than death. Cut his dick off, cut one eye out, cut pieces of his skin bit by bit, cut his tongue out, poke him with hot metal rods avoiding vitals every day, etc. basically what Griffith endured and more.
Honestly i feel like, yuri wanted to get evidence by recording or in case something happened she wanted to leave something behind but its yuri's fault for going alone and confronting him. She could of just called authorities related to child abuse and everything would have been fine. Its better than this even if she didnt go alone anyone would have been fine, i guess author chose this way to make her impusilve when she learned that the person she considered her little sister getting abused. In the last chapter they should go together back to mom and live as yuri wanted, be a real family and maybe with sumire too.