We really haven't seen much of Apoo's abilities to judge but but brook puts people to sleep with his music or rile them up with his music. I would assume if Apoo finds a way to be louder or not hear Brook, he can have an easier time. I just want to know how loud Apoo can get.
Sound can be a very powerful weapon. Ever had a loud noise go thru your ears suddenly? Sound waves can actually tear you apart if they hit you hard enough. The vibrations can really rattle your bones and what is Brook made of? Hopefully after being alive for so long he knows CoA haki. It hasn't been shown but it's possible he knows the basics? If noise can hurt your ears it can also ruin your balance but I mean who knows how that can play out, it depends if Oda cares to include that medical aspect into the story but he should...
Long story short, I feel that if Apoo can get loud enough he can just shatter Brook he will win. On the other hand Brook is cunning and can run on water and drink milk to heal lol. He's also fast, Apoo himself doesn't seem too fast to me but sound travels really fast and bounces off stuff. At the end of the day we need to see more of Apoo's capabilities for our collective edification before any of us can make a good judgement. The good news is soon we will see him in the Wano arc so the wait may be over soon. They already introduced Hawkins super quick so once the manga gets closer to announcing the other calamities, Apoo will appear in all his awesome awkwardness. Brook needs to get his ass on the scene too.