Lester Levenson, whose teachings inspired the Sedona Method, said that if you can feel free in relation to your family you have achieved a high level of freedom. By free he meant imperturbable - free of negative feelings, free of expectations, and free to be with them or not be with them and feel at peace.
Lester understood that our basic core programming takes root in our families of origin and much of this programming is unconscious. So when we relate to our family members we are often relating through the filter of that programming instead of who they are and who we are now.
Feeling stressed around the holidays and being "triggered" by your family offers a great opportunity to release and untangle core programming. Any releasing you do with regards to your family will net you big gains and will carry over to other aspects of your life.
Here's how to stay grounded and in the present:
First of all, please try not to beat yourself up or give yourself a hard time if you get triggered by family members. It's very common. I still do.
Secondly, see if you can do your best to stay grounded, breathe consciously, and stay present - in your own body and with yourself when you're with family. If you can, during your interactions with them, take a moment to make sure you can feel your feet and the different parts of your feet. Also see if you can feel the muscles in your chest and/or belly as you breathe. Feel them expanding and relaxing. I will sometimes sort of pinch myself (literally), as a way to remind myself to feel and be in my body. You can also repeat the word "now" softly and silently to yourself as you breathe.
Simply practice this when you think of it and approach this exercise with openness and curiosity - as best you can:).