Mexico has good things in store for it After the Pole-Shift. The southern extremes of Mexico will be no more and replaced with a new ocean where the land bridge connects the two continents. The volcanic belt just south of Mexico City that lays west to east and stops south of the Yucatán peninsula will be active for many decades into the After-Time, but the good news is, that the volcanic ash-fall will extend out into the new southern Mexico ocean: this is a new wind direction for Mexico since North America lays on it’s side with the Tropic of Cancer (30° North Latitude) passing old west of Puerto Vallarta and will run vertically up through central Mexico, this splits the country into two weather systems: the Pacific and the old Gulf of Mexico. Adding to the good news, is that the old Gulf will expand considerably due to the Pole-Melt by the end of 2024. As a result, both weather systems will provide much-needed moisture for growing food and very good for general Living in Mexico. The usual coastal danger precautions apply, this and more is all detailed in my main safe locations map for Mexico.
Finally, Mexico will have a warm contiguous land mass surrounded by ocean on three sides making it a wonderful place to plan a life for the After-Time.