That won't have been the reason the drone crashed.
His recorded flight data might show what actually caused the incident.
Using rice is much less effective that rinsing with alcohol and letting the drone air dry.
As I said, my brother was flying his drone over the land, then as soon as he flew at low altitude over the water, the drone did a sudden jolt, and fell out of the sky, as if the sensors had gotten confused. When he got it out of the water, it was...
My brother crashed his DJI spark in fresh water today, because he flew low over water without turning off the sensors! Thankfully It seems ok and he has opened it up and put it in a big bowl of rice. battery seems ok still to. So, lesson learned! 😢😏