If this happened as described the person who did this should be handed over for trial in Mexico. Which isn't going to happen. Maybe the Mexican government should send their army to the border to protect their citizens.
It might have been an accidental firing, it may have been some retard racist, it may have been twenty other things. Either way, two friendly neighbours that need each other's economies would not and should not start murmuring about war over relatively small incidents like these.
Yes, it hugely sucks for the victim and the US should financially pay for everything but that is what you have diplomats for.
For those wanting more about Border Patrol killings:
Similarly, the actions of CBP officers also affect the number of migrant deaths. The CBP Office of Professional Responsibility reported that 151 CBP-related deaths occurred in FY 2021. This figure includes migrant deaths that occur in CBP custody as a result of use of force by a CBP officer and vehicle collisions that occur during active pursuit by the CBP, among other causes.
In June of 2022, the CBP reported a use of force incident that resulted in the death of one individual. Migrant deaths that resulted after high-speed chases by the CBP in 2022 have been documented in Arizona, New Mexico, and Texas.
These incidents are currently being investigated by Homeland Security Investigations.
However, the comprehensiveness of CBP data has been scrutinized by the GAO, which stated in April of 2022 that “Border Patrol has not collected and recorded, or reported to Congress, complete data on migrant deaths, or disclosed associated data limitations.”