If by Generic form, you mean IMM 0008, then his name was incorrectly entered in the form where only dependents should be listed.No, he is 38 or so.
We had to put him on the application(just in that generic form) as a son of applicant. Just like all the brothers and sisters of my wife's parents.
Him and your wife's name (and other siblings over 22 years old) should only be listed in imm 5645.