how about php files and others ?
The style.css allows other files to "know what's going on" ... lol. Everything in the child theme over-rides the it's counter- file in the mother theme ... except images. You don't need to worry about images. (That's whole new can of worms I'm not getting into. )
What happen if there is an update from mother theme (ex.adding additional codes) and affecting the files that we copy and modify in child theme ?
Changes in files like that are handled by the mother theme. The mother theme files are actually not 100% over-ridden. That's why it's important to keep updating the mother theme. The child theme will benefit from any improvements. Don't worry about it.
In over one year of theme updates, the only time my child theme had a problem was when they changed the name of "home-page.php" to "front-page.php". That was a terrifying day in my child theme's history and was fixed in 5 minutes by putting a new copy of the file into my child theme and copy/pasting the edits in the old "home-page.php to the new "front-page.php" ... something that only ever happens when the Developers drink too much Vodka.