How to list an unfinished PhD on a resume

Don't worry, this is a very understandable situation. You should just be honest about it.

I don't think the fact that you started a PhD but were unable to finish it due to financial and family circumstances will be counted against you in a professional context, especially if you otherwise have a record of successful employment.

It would be more of an issue for pursuing a further career in academia (either another PhD or academic employment), since the PhD would be highly relevant to the work you wanted to do, and you might not have any other equivalent experience on your CV. But outside academia, I don't think it matters much at all, particularly since you have been employed since then.

This situation happens to people and it is often challenging to figure out what the next steps are. So, be happy that you are making the step to pick up the pieces and move forward!

You should definitely include the PhD program on your resume, especially if it relates to fields that you are applying to. Where you most likely want to address this issue is in your cover letter. If you are transitioning out of academia altogether, you can give professional explanations for leaving a PhD program where you wouldn't have to explain the personal challenges you have faced. For instance...

"I realized during my doctoral studies that I prefer more hands-on work that would be offered in industry positions."

"I enjoy my field very much, but am looking for positions that offer more stability and consistency in my schedule and pay than in academia."

Those are just examples. If you are seeking a position within academia that does not require the PhD, you can use similar explanations ("I have learned that I'm better suited for administrative positions" or "After starting my doctoral studies, I realized that my passion lies more with teaching than research.") I'm not sure if this would be different in Mexico or not. I hope this helps!