He has a round trip ticket with a 10 day stay, will they not let him out from the US? He is a US citizen... the return is on the 28th of December 2009, expiry 10th of January 2010... If there is no problem from the DR side, we are fine to go.. i think...
They have to let him out of the US. And I checked and there is nothing on the DR US Embassy page about requiring a passport to be valid for six months.. so, yes, you should be fine....
Obviously you are young and therefore are comfortable taking the risk psychologically......(I remember the days!)
However.. just know that if anything happens so that he misses his return flight and has to renew his passport here in Santo Domingo, it is going to cost a LOT more than the $150 since there is no 24 turn around here...
So he had best travel with a copy of his birth certificate and Social security card and other photo id... just in case...They may let him in with those...after some detention and strip searching, etc etc etc...
And, of course, if you have to come back here to DR1 because he has to renew his passport in the DR, I am going to rag on you without mercy!!
Enjoy.