Could you please tell me if I am using "as if/as though" correctly? Is there a difference in meaning?

Enthusiastically he kept living his life as though he were not diagnosed with a terminal disease.

The night was bright as if it were a day.

Her eyes looked as though two flames resided in them.

She feels tired as if she did not get enough sleep.

He demanded that his friend appologize as if his behaviour were not offensive.

On -20C she wears light clothes as though it were spring outside.

Thank you very much
Hi, Spring

I understand "as if" and "as though" are the same. All of your sentences look correct to me at least grammatically. But I feel it is tough to catch the exact meaning of "He demanded that his friend apologize as if his behavior were not offensive". I rather feel "not offensive" should be "offensive".

I don't have an answer, but it is as if you were reading my mind. :<) That is exactly the question I want answered.
 paco2004's reply was promoted to an answer.