It depends how they look on him, I guess. Sometimes I can't even tell much of a difference between men's and women's pants, especially if they're straight-legged or skinny jeans. Personally, I think that as long as they don't have flowers all over them or are a style only seen on women (flares right now, though those could come back for men eventually), no one will ever know the difference. Pants are pants.
I'm answering that assuming that by "okay" you mean, "Do most people find it attractive?" In reality, I don't think it's any of my business what anyone wants to wear, as long as it doesn't break any laws.
Hell no. While I would not throw tomatoes upon seeing a guy in women's pants, I sure as hell would never think of him as dating material. I would just assume he is gay and keep it moving. I like a man to be a man, not wearing feminine jeans WTF