Immigrant questions

I’d greatly appreciate if some one can help.
My mother has been had the GREEN CARD since June 2002. She is going to file a immigrant petition for her divorced son(40 years old) and grandson(will be 18 years old by the end of December). In the form I-130 there is one place to fill out the information of the son. Does any one know where to fill out the grandson’s information? Now the grandson is almost 18 years old. By the time his father gets the visa #, will the grandson be aging out? Thanks in advance for any help!