Hi Andrew,
Thank you for your reply. Then what about the default theme, Twenty Fifteen? Is it possible to modify the Twenty Fifteen theme into something complicated like a non-free theme from themeforest only by editing the functions.php of a child theme?
I kind of would like to know the coverage of the functions.php of a child theme. Actually, we paid and asked a mid-level developer to create a website using and modifying a theme that we bought from themeforest. And he wants to modify the theme by editing original php files of the themes, not the functions.php of a child theme.
