Grandma wants to attend wedding, rest of us think it’s a bad idea

To clarify first off, I would absolutely love for my only two grandparents to attend my wedding next January. However, the issue is that my grandmother has been in fragile health for a few years now. She was hospitalized last year a few times (non Covid issues). Her cognitive state is not always the clearest these days (we suspect early dementia), and she is physically very frail. My grandpa takes care of her and he agrees with us that she is not in good shape to travel for my wedding; they would be coming from Canada to Texas in the middle of winter, requiring a two hour drive and two flights. It is a whole day of travel and is tiring even for me, let alone people in their early and mid-80s.


The problem is that my grandma has evidently really perked up at hearing about my wedding, and she insists she is coming. My aunts who live close to her have told us she is asking about buying a dress and where are they staying and so on. My mom had previously told her that no, she cannot come because she is not strong enough for the trip. My grandma got (understandably I suppose from her perspective) quite angry and was yelling at my mom on the phone about it. My grandpa knows she cannot travel but I think he wants to avoid a fight too so he just lets her talk as though they are coming.
Our concern is the travel alone will wear her out, and that she could have an episode at the wedding (we think she has some nerve degeneration where occasionally she locks up and falls down). They don’t have health insurance here as they are from Canada. But she really seems set on this, and I can understand it would be very frustrating to be told you are too old and frail to come, but the reality is she doesn’t quite admit or understand her physical limitations anymore.
I am looking for any ideas or advice on how to handle this further. How can we get across of course we want her there, but we are very concerned that the trip would be detrimental to her health?