How do you apply he-who/him-whom rule to these 2 sentences?

1. "He would not tell me who/whom he saw in the shadows that faithful night."

2. "In desperation, Belinda sought help from Professor White, who/whom she knew preferred playing solitaire on his computer to assisting students during office hours."

If the sentence already uses "he" (in the subordinate clause) wouldn't that mean that you use "who," and the same thing with "him-whom."