How normal is it for a man to sleep in a nightgown?

I prefer my boxers or go fully naked. But go ahead with what makes you comfortable (but nope, not that normal)

well it might help the gentleman down low be free and air out all night.

Not normal. I sleep in a nylon nightie every night now. Most nights I sleep in the spare room. My wife knows I sleep in a nightie, but doesn't tell anyone else I do.

It's definitely more normal than you would think as I usually wear women's nightshirts because they're much more comfortable to sleep and lounge around in over constricting male boxers or shorts. It's just more freerer down there if you know what I mean. I've known or know men who wear women's nightgowns or nightshirts.

I think the only real difference comes on how feminine the nightgown is that you're wearing because that's probably crossing over into crossdresser or tranny territory but if it's a simple looking nightgown or nightshirt you're wearing that's normal.

Probably normal if you're a cross dresser or a trans.