Unless I'm thinking of something else, some people are more prone to it than others. I had an eye exam this year and the Dr mentioned something like 'and I'm sure you know about this, but your left eye is prone to retinal detachment . . .' NOPE NO ONE EVER TOLD ME THIS. It only makes me like 1% more likely to get a tear, but it's possible. Maybe your mom had the same issue with her eye? It sounds like she had it addressed quickly and that's the most important thing. It's highly treatable as long as you have surgery right away, from what my Dr told me.
I'm glad she's doing well and enjoying California!