Data recovery from a liquid damaged device is quite a risky job if there has been a long interval since the device was damaged. The more its late the chances are few to get it back, because of coercion which keep growing on liquid damaged devices with the time.
So the key to recover your data is to bring device for repair as early as possible.
Physical damaged devices can only be brought back to life if the logic board has survived. Some times damage is so bad that it even cracked the logic board inside of device. But we always try our best to recover and restore your data.
In Apple devices we can only restore your data if your iCloud backup was up and running before the damage is done. So it is advised to always keep your backup on so you can recover your data in case of any damage.