Yes, you can do that. I'd guess there's something a little off with how you've set things up, but it's difficult to know without more details.
How about some screen shots. Maybe 1) the scene tree, 2) the script on the parent, and 3) the script on the child?
For the above to work...
- The parent node must have a script with an
- A direct child of the parent must have the script containing the
get_parent().Income = 25 (for example)...