Is there a way to change the Facebook messager notification sound?

My husband is constantly getting Facebook messages. He phone dings all day and all night. I'm really starting to hate that sound and I'm sick of checking to see if it was my phone, or assuming it's his and missing a message.

So I'm wanting to change the notification sound on my phone, but I'm not sure if I can. I know I can turn the sound off, but I would like to hear a notification since I run certain parts of my business through Facebook.