admin-only-categories : how to hide parent, but show child

I’m using the “admin-only-categories” plugin,
it’s exactly what I wanted EXCEPT

When I hide the parent category,
the child categories are hidden too.

I want to hide the parent (1st-level) categories to all but admin,
but want to make every child (2nd-level) categories available.

So my question is:
1. is there a way to hack this plugin to make this happen?
or
2. is there another way/plugin to do this?

Thanks!