Repeated Crankshaft position sensor failure

Hey guys, hoping someone can point me in the right direction. My friend owns a 2000 e38 and in the morning when it’s misty or dewy the moisture gets into the engine bay and the car won’t start. He tracked it down to the crank position sensor. Every time he replaces it the car will turnover and start. But it’s starting to happen daily every morning here because it’s very cold. Tonight he went and got a new sensor, installed it and it started up and then died. Then he tried to start it again and it just turns over but won’t start. What are some things he should look at?

Thank you!