[Tense]: Present tense and continuous tense I met a strange usage of tenses ( and form) like: > I guess that it might be some kind of word play by using different tenses (future and present continuous) like: > I wonder it could be said that he would't change no matter what or he was a stubborn guy since the beginning. It just a blind guess so I hope someone can explain in more detail about the usage of tenses in this context.

literally, "He/She doesn't change/never changes."

literally "He/She hasn't changed."

I'm not sure where "stubbornness" comes into play, since I don't know the origin of the quote. But essentially you are correct, the speaker is using the subtle difference between the two tenses to make a point about the person. I might translate it into something more like:

"I don't know whether to say he hasn't changed, or he can't change!" ... In English, these are different tenses than the Japanese, but the sense of the sentence might be conveyed more faithfully.