As much as you do not want to be an "accomplice after the fact" (and during)- please still help your mom...even though you vehemently disagree.
Her mind-set is very strong, and yes it's hard, but in her mind YOU are wrong. I totally understand your side, but at least spiritually, your mom will know you love her by honoring what SHE believes in - even though you (and we who support YOU) KNOW that she is WRONG!!!
Love to you, and, we are always here for you when you need to rant!