Is is dangerous to use cedar wood essential oil if also using warfarin?

My 83 year old mother is on Warfarin for AFib. She has trouble getting any sleep at night. We have looked into several natural herbs that are supposed to be sleep aids, but all have been not recommended for Warfarin users because of danger of bleeding. I’ve been told a drop of cedar wood essential oil on the bottom of her big toe would help her sleep. Is that a dangerous combination?
Thank you.