Why Does NyQuil Cause Vomiting In A Person With Low BP?

My 42 year old mother is very very sick. She vomits, has a fever accompanied with chills, diarrhea, severe aches, vertigo, and major headache. When she takes Nyquil, she vomits it up, as well as with everything else. She has Mutual Valve Prolapse and Arythmia, as well as low blood pressure. An alternative she came up with would be to retain Nyquil under her tongue to absorb the Acetominiphine out of it. Please respond ASAP, We are very frightened at home.