the file placed in the child theme is not included

I have modified the theme.php file located in the parent theme in the “Includes” folder, and I have placed it in the child theme also in the “Includes” folder, but my changes are not included. WordPress only reads the file placed in the parent theme folder. What is the reason for this? What should I do the modifications are included when the file is located in the child theme folder? Alternatively, how can I override a function from includes/theme.php in functions.php? I can’t override the function because there’s a redeclaration error.

Edit 7.05.2020

@JacobPeattie – Thanks a lot. I read it. I don’t know if I understand it all right. My English isn’t very good yet. I wrote so in functions.php:

It was successful added, but doesn’t work.

Maybe it’s usefull information:

File theme.php is added in functions.php file in parentTheme/includes folder in this way:
require_once BIMBER_INCLUDES_DIR . 'theme.php';

Function is called by ‘echo’ in another function.

Here are php files: