Have you asked her if she wants help?
If she does want help, I'd suggest showing her the console cheats, perhaps by binding some commands to a few keyboard keys.
If you jump into a game with her, you'll change the dynamic of her fight against the game more than giving her the option of just getting full ammo and health at the press of a button.
You obviously know her better than we do, so the decision is ultimately yours, but remember that if you just jump in to the game it could be seen as taking over the game and telling her that she isn't good enough.
What ever you do, talk with your partner first and make sure you are on the same page before doing it.