To treat corrosion damage follow the following steps:
1- please stop turning on / plugin in a device with a mysterious liquid in it and take out the battery.
2- take the device apart, and uninstall all it components which are detachable without soldering
3- make a warm tray of isopropyl alcohol 70c and use a soft scrub tooth brush to scuba the components of the board, and all of the connectors that attach to the board from all modular parts
4- let the scrubbed parts stand at room temperature for 2-3 days so the evaporation of the alcohol can remove all the little bits of dirt
5- reassemble the device and give it a go
Unfortunately the device was probably permanently damaged before you received it from you friend. Liquid damage causes little shorts all through the device that damage components on a very small scale, resulting in non-repairability.