In your first example, you have mixed up whose with who’s. Who’s is a contraction of who is ; whereas whose is the possessive form of who or which. when used as adjective.

What is that girl?

What car this is?

What is Melbourne’s public transport system?

Who are you at the door?

As for your other Example, it’s perfectly valid to use who when referring to an object. Is it correct to say “the desk whose drawer was broken by my brother”? The second example mentioned above is word whose in just that manner.