Compassion fatigue is a known phenomenon:

https://en.wikipedia.org/wiki/Compassion_fatigue

It is routinely studied as part of training for helping professions such as social workers and counselors.

People who care greatly and deeply and effectively are vulnerable to compassion fatigue. I think ten years spent helping parents who had dementia, mostly on one's own, would exact an enormous toll. I deeply admire and respect what you did. And it makes sense to me that one might find it painful to, and therefore be reluctant to, immerse oneself in hearing about the care needed for other people's parents as well.