Classic Hax. You have to be pretty open-minded and self-aware to be able to sympathize with those who appear to be (and may objectively be) more fortunate than you are.
Or she’s genuinely unhappy. It can, of course, happen amid gaudy equity, lovely kids, an attentive spouse, a flexible career, stable finances and ambitious travel; just because these have societal value doesn’t mean they’re valuable to her.
And just because the decisions were “very-thought-out” doesn’t mean they were the right ones for her. If a person’s baseline understanding of herself is a degree or two off, then her choices can lead her, over the years, hundreds of miles off-course.