I have taken apart a few commandos now including my friend's to solve a similar problem. I might be able to help
First things first, if it was water damage you could try letting it sit overnight in a bag of dry rice. Fixed one of my problems once
If you need to get into the phone, this could compromise the watertightness (if you cat steals the rubber band inside it
)
The first thing you need to do is find a flat head to get into the tri-wing security screws. Or you could buy some "tri-wing security screw drivers". Up to you.
If your going with flat head, then you should get a size around 1.0 and 1.5 for the inside screws.
I will make a quick mini-guide over the course of a few days if you want. Assuming I can get enough time, do you want text and picture, or video?
Also, if the speakers themselves are broken, I would be more that happy to send some good ones to you.