My grandpa's last living sister is the same way. She's upset if we even call her down in Florida to ask about "dead people". Some of it's probably a generational thing.
If you have a wedding date and approximate year, I know one of the secretaries at Notre Dame well enough to call and ask for info. She's the only one there who's happy to speak English. I've bought enough masses through the years to gain her trust.But just because your aunt saw some of the Tessier names at Notre Dame, it's not necessarily a positive sign. There were so many Tessiers with the same set of names that it's almost impossible to tell one from another. I've come across over 200 Jean-Baptists through the years, let alone Guillaume, Pierre, and Paul.She may also have seen the plaque on the front door noting that the basilica was built on the land of Urbain Tessier-Lavigne and taken more from that than there is.
If you have approximate dates/ages for Alex and Fannie, I'd be happy to do some legwork and see if there's anything else to be found. Any records pre-1930 will be available to us.