A friend of mine is half of Mexican descent.  She was born in 1968. 
She is a U.S. citizen, born in the U.S.  She has described to me that
she has some sort of Indian (yes, Indian, as in Native American)
number.  Apparently she has one while her brother, who was born in
1970, does not.  Apparently, the threshold for what percentage of
Mexican descent you must be changed some time during this period
(presumably above 50%).  She got all this from her mom and dad once
upon a time.  As an aside, she has a child whose father is of Mexican
descent, so her child is 75% of Mexican descent.  She is from the San
Juan Capistrano area Mexicans.  ANYWAY, *apparently* having this
magical "number" entitles you to all sorts of benefits, such as
college education, and who knows what else.  She is interested in this
both for herself as well as her kid.

So, bottom line:  Asssuming this is for real, how does she go about
locating her number (she is not on good terms with either of her
parents) and obtaining her benefits?  Please be specific (i.e., I'm
not looking for "call an attorney who specializes in this" or "check
with your library"!).  An added bonus (but not necessarily required)
would be what benefits this entitles her and/or her child to (a web
site link would be sufficient here).  (I'm only relating what I'm told
and I realize this
isn't a lot to go on.)  THANKS!

Before getting into the matter of benefits, your friend will need to
determine which tribe or nation she belongs to, if any. In the San
Juan Capistrano area, the Acjachemen Nation (also known as Juaneņo) is
a possibility.

Contact info for the Tribal Office is here:

http://juaneno.com/