[apsychas]

Wouldn't the wife have to move to the US within six months once she's approved for the green card?

[wesleyd]

I recently learned about "commuter" green cards, which let folk live in Canada or Mexico: https://www.uscis.gov/ilink/docView/SLB/HTML/SLB/0-0-0-1/0-0...

[proberts]

That's a good summary but essentially one needs to demonstrate frequent and regular trips to the US for employment to qualify.

[proberts]

Yes, assuming that she went the immigrant visa route through the US Embassy in Mexico rather than the adjustment route through USCIS.