The above post is incorrect.
IR-5 petitions are usually processed by the service centers in about 5 months, transferred to the NVC, then to the consulate of the country where his mother resides. The entire process usually takes 10-11 months from the time the I-130 is submitted.
The initial petition requires the I-130, the USC's birth certificate showing his mother's name (with translation if necessary), the USC's naturalization certificate, and if he changed his name, the documentation for that.
Good Luck
