You need to list all his family members in the I-130, but only need to provide the photocopiers of your brother's birth certificate and your birth certificate for the I-130 filing. You do not need to provide the other members' birth certificates and your brother's marriage certificate for the I-130.
In the future, only your brother needs to file DS 260 application for the immigrant visa. The kids will be age-out and not qualifed for the immigration benefits as the derviatives. His wife does not need to file DS 260 if she does not immigrate to US.
