Sounds like Mexico needs to get their shit together.
I love Mexico. I'm there every few months. but yes they have a lot of their own problems.
In general though I'm a big proponent of Marshall plan diplomacy.
I'd kick out every Visa overstay and even end birthright citizenship. If neither parents here legally kids shouldn't be either just because someone figured out where to game the system. I'm happy to take in more refugees. That's a more moral use of resources than people that just want better jobs.
But I'd also pour tons of money into developing our southern neighbors in the same way that we rebuilt Europe and entrenching those relationships for a century later.
We should be shoring up our sphere of influence And to do so with many of these developing countries costs very little on our end and results in long-standing economic improvement and potential trade between our countries whereby we are paid back anyways. And the development stops the influx.