And welcome to the Polish forums.
What can I do to make him feel like home?
Try to set up a cheap means of communication between where he is in Mexico and his family in Poland.
Skype is free and you can also have a webcam so he can see his family.
Every now and again try to have "Polish night" when the dinner is Polish, with Polish music and a shot of wodka ;)
Contact the Poland Embassy in Mexico and the Mexico Embassy in Poland and inform them of your move, give all your details, find out of any meetings they have of Polish ex-pats in Mexico.
Also see if there are any Polish in Mexico websites, where he can find out more information, like this one: internations.org/expats/members/mexico/polish - Polish in Mexico - Connect with Polish Expats in Mexico