Hi,
So the bad news is salt water is electronics' worst enemy. With that being said, the device still shows sign of life which is good. What you can do is follow the ifixit teardown guide to take out the logic board. After you take it out put it in something that has greater than 70% alcohol and scrub it with a toothbrush. dry it with a hair dryer or just leaving it out to dry for a few hours and try to reassemble it. If the water damage was minor, it should work.
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