I am so sorry that you're dealing with this tension during Christmas. I'm sure you are dreading seeing them again. It is SO frustrating dealing with family who can't put their own feelings aside to make a stressful time easier for you.
I'm with everyone else about setting boundaries now. Draw the line at what kind of unsolicited advice you'll accept and what you won't. My mother is a control freak, so I get my own share of advice that if not followed, I'll be harassed until I do what she says or I'll be condemned as a bad mother/wife/daughter, etc.
DH and I have set boundaries and will continue to do so probably until the end of time!