I will do a video about it, but I think overthinking this tends to get some people a bit confused. When saying the value of the dollar increasing actually benefits Mexicans in Mexico, that is. It’s easy to look at it from just the US perspective, however it’s normally an incorrect and biased view. 
Let’s look at a few points: 

   1. Legal, (“because they were born there”) and Illegal (“that came over to work and send money back to their families”) are not the only status of Mexicans in the U.S. There are many in America that are legal because they became a citizen and are naturalized. Even if they never sent a dollar to Mexico, they are just as legal as you. There are many reasons and many statuses of people from other countries in the US.  

2. The US dollar rate going up does not necessarily have a good affect on Mexicans. Not as a whole. It only has an affect on the Mexican peso if exchanged. Everyone in Mexico doesn’t have someone to send them American dollars, so their life is only governed by the Peso, no matter what its value is. When affecting a US based company in Mexico, it then effects the individual Many could care less what the value of the American dollar is when they only get paid in Pesos and they pay their bills in pesos and attend to their families needs with pesos.  

3. If it does affect a U.S. based company, it normally never affects the individual people working there. That’s because the company may be making more money but they still pay the employees at the same low salary and in pesos. The prices of things around him/her may be increasing while he value of the peso has been decreasing. Yet that person still has to pay for their home, cars, etc out of their same low pay. Basically, things are costing more but they haven’t got paid any more. 

I fail to see how any of this is a “benefit” to citizens of Mexico.  

When attempting to live in another country, you must have the attitude of adjustment and adaptation. You must be willing to adapt to the new countries ways and standards of living and not expect them to adapt to yours.