Answer: "His brain becomes as soft as cheese" is a simile
"His powers of thinking rust and freeze" is a metaphor.
Explanation: Simile uses "like" or "as" in the comparison. A metaphor creates a mental image by associating characteristics of something like rusted metal with another thing-- like a brain-- that doesn't actually have the characteristics; it's just to help you imagine.
Idek this makes no sense. Sorry, but your on your own
