I would love to hear more about why this problem is "genetic".
There is a test to show which germs are in your mouth - it is called an Oral DNA test - and this may be very useful for her - if it has not already been done.
Periodontal disease was thought to "run" in families - but we now know that is spreads on toothbrushes and when people kiss and share food.
I would like to learn more.
If you want to start somewhere, I think Zellies and sufficient xylitol could be a huge help.
Most of all I would suggest using the Complete Mouth Care System www.DrEllie.com
I have taken people who were about to have $6,000 worth of gum surgery and make them healthy again.
There are things she should avoid: any whitening products or peroxide, baking soda, drinking soda or acidic drinks, chewing gum with sorbitol and artificial sweeteners.
Hope this helps.
I offer telephone coaching help - www.DrEcoaching - and this may be useful for your friend.
Let me know,
More information can be found on this topic and more at: www.drellie.com