I want to know the process and amount of time it takes to get a visa
for a Mexican citizen to come stay with my family and study English
for 1-2 months in the summer.  This is for a Mexican student who will
be graduating from high school this year and entering university (in
Mexico City) this coming September.  His family is of very limited
means, and so doesn't have the benefit of bank accounts, etc. in
Mexico for immigration documentation.  He would be studying in a
full-time English program (Berlitz, Boston Language Institute, or
something similar) which we (in the U.S.) would be paying for.  He
would live with us, and we would purchase his (round-trip) airline
ticket.