Should she die sooner and the funeral were to be in that week should we cancel our hoilday?
In that case yes, of course, but at the moment you do not know. Some very sick people do rally and a prognosis is just that, a forecast and not absolute.
How close are you and what do you think she herself would have wanted you to do?
I think you could phone the travel company and/or insurers and explain the situation, they may be sympathetic.
The Republic of Ireland and their tensions with migrants.