Hello @heruprambadi and welcome to our forums 
The use of checkbox_boolean doesn’t take any options at the moment. So the use is as follows:
$crud->fieldType('field_name', 'checkbox_boolean');
Which only takes the arguments 0 or NULL (depends if your field is nullable) and 1 if checked.
This is currently hardcoded values and I would like to revisit it to be honest for Grocery CRUD version 3 which is removed for now. I guess your point is valid, to have custom values but maybe the field name also will be a different one such as checkbox instead of checkbox_boolean.
Regards
Johnny