Problem:
The user would like to enqueue his child theme's styles after blocks styles.
Solution:
Toolset Blocks has implemented a lazy load mechanism for its styles, using Javascript. If you want to use its style as a dependency, you will need to disable the lazy loading mechanism. That can be done using a constant in the wp-config.php file:
define( 'TB_SCRIPT_STYLE_LAZY_LOAD', false );
After that, the styles will be enqueued in the default way, and you will be able to set it as a dependency for your child theme's styles.
So you can depend on the "toolset-blocks-css". For example: