Those widgets are called cam and dowel fasteners (or cam nuts and cam bolts). Pretty simple stuff.
I have been there as the go to guy to call that can fix or diagnose things. You will have to say no to some things. She will get pissed. But eventually she will be weaned from Jeff.
If you want to get her something for Christmas on behalf of the kids, get her one of those Home Depot or Lowes home repair books. Probably not a good idea to get "Home Maintenance for Dummies".
