The Brother’s Keeper side quest in Hogwarts Legacy becomes available during the Find the Secret in the Restricted Section main quest and comes with a suggested level of 17. Travel to Upper Hogsfield which is north of Hogsmeade. Once there, look for Dorothy Sprottle who can be found working in her garden and speak with her. She’ll mention Bardolph is missing and ask you to look for him. Before setting out, stop by Claire’s shop stand near the main square of the town to speak with her and get more info on Bardolph.
You’ll then want to leave town heading slightly northwest. You can access the path leading northeast from the Floo Flame outside of town. This will eventually take you past a river and road sign. Continue heading northwest to reach the Jobberknoll Den.
Head to the top of the den (don’t go inside) to find a group of Inferius. After defeating two groups of enemies, a boss will show up. Defeat the boss then check in the tent to find one of Bardolph’s journal entries. A second can be found southeast of the tent on a broken section of the building. Next, return to Claire and report your findings to complete the quest and receive an arrow-black wand handle.