There's nothing harmful about sleeping with a fan on.
I've been sleeping with a fan on for years and nothing has happened to me.
South Korea has a fear of death by fans because someone was found dead with a fan on but the person who died didn't die because of the fan.
The person died of other natural causes and would've died regardless if the fan was on or not.
You will not die just because you sleep with a fan on.
I have been sleeping with a fan on for years and so has many other people and they never died from it or gotten sick from it.
I love the white noise of the fan and will even keep the fan on even though it may not be blowing at me because the sound of the fan helps me sleep.