First off welcome to the forum and sorry to hear about your crash.
Salt water will kill your battery pretty fast so you will need to get a new one. As for the bebop the best thing you can do is open it up so you can wash off the electronics of all the salt water. The salt from the sea will in time start to corrode the parts inside unless you clean it good with fresh water. You can then let it dry for a few days in rice or a good open space where it will get plenty of air. You don't want it to sit in moisture so getting it dry is the key. Don't be in a hurry to fire it up before you are sure it is completely dry.
As Agustine says salt water is a killer to electronics. Ideally you would have flushed the bebop through with plenty of fresh water when you found it. I know from having a waterproof action camera that wasn't waterproof that it does not take long for the salt water to corroded the circuit boards. If you did not flush it out with fresh water thoroughly within a couple of hours then the damage may already have been done. Taking it apart and examining the circuit boards will tell you a lot but I cannot see the camera surviving. Even the micro SD card contacts may be ruined. Sorry to be a bringer of bad news.