Shooting in the dark here...but do you have family back in Mexico?  Or do
you know the name of the store that you bought the food from?
 
You could see if your family/friends or the store where you bought the
food from originally could ship it to you.  I am sure it will cost more
but right now you don't have a choice and from you post you seem like you
will do almost anything for him.
 
Maybe there is someone on the FML from Mexico that might be able to help
out also.  Anyone out there able to do this?
 
Have you tried some "wet" kitten/cat food?  He might at least eat it.
You can also give him baby food.  If he likes it you might be able to
put some on the "new" food and get him to eat.
 
Joanne
[Posted in FML issue 3735]