"Refusing to assist someone in doing something" seems to be different from "forcing someone to do whatever was already going to happen if they didn't do the thing you refused to help them do" to me.
It seems to me that it's not "force" unless there's an alteration to the natural course something takes by default. So in this case, "continuing to live for awhile" is the default natural course. Refusing to assist someone in altering that natural course isn't the same as "forcing them to continue living."
Likewise with pregnancy, the default natural course is to remain pregnant until miscarriage or birth. Refusing to assist (or allow someone else to assist) someone in altering that natural course isn't the same as "forcing someone to remain pregnant."