I copied inc/helpers.php to child theme directory.
Then helpers.php has some errors.
I fixed them.
For your reference:
No check using function_exists
Wrong check using function_exists (class_exists is correct)
I hope you are well today and thanks for helping out here in this forum.
I could confirm the issue on my test site therefore notified the theme developer about this so that it will be fixed.
The issue will be fixed ASAP.
Your help here is really appreciated.