Yes invite them! The more the merrier. Make it RSVP just to them so you can have some lines handy.Like ; Has wisdom not accompanied your age as to know how to mind your manners in the home of your host?
Then say; I hope this is a word to the wise.
You could also let it be known that gifts are welcomed.
Then again you could be underestimating them and their behavior may be appropraite.