My cat is mimicking my lost cat's meow?

by Isabella
(USA)

It’s been about three weeks that my male cat has been gone. My other cats don’t really notice since he’s hardly home anyway. Before I mention his sister, I'd like to state that he has a very loud meow. I wouldn’t be surprised if someone hurt him because he can be annoying.

His sister has the cutest meow, but recently, late at night, she meows EXACTLY like him! When it first started I thought it was her brother, but I would be very disappointed by who I found!

I couldn’t believe it was her making it, since the two sound so different from each other. Is this normal behavior? Maybe she misses him, and she did act very sad before she began to mimic his meowing.