As I understand your doubts and reflections about the issue, still, I believe that a writer is in the position of freely writing about any subject... Isn't this also a form of freedom of speech? In fact, a writer's perspective can provide a different angle to the story, but it doesn't mean it's wrong, it just means it's different. All narratives add up to the final result, and none of them are biased... They're just what they are: personal perspectives.
Writers write about a story that forms out of their thoughts, intents, reflections, observations, feelings, etc... So, you wrote about a family's dramatic story from your point of view, but this is not wrong. Actually, it could be beneficial to Mexicans knowing that also people from other cultures can relate with their feelings to their story. It's positive for white Americans acknowledging such inhumane forced family separation.... Maybe this can change in the future. After all, you are a writer who tells a story (the story of a family as you can interpret it); you are not a journalist/historian who merely reports the story, and for this reason, it must be absolutely correct. You have the freedom of writing whatever you want.
But I respect your decision as I get that it's such a delicate issue, especially when you know personally those people. Here, the most important fact is that you are at peace with your decision.

Thanks for sharing your considerations.