Can a Communication student earn double majors or a minor degree/certificate in another school?

Hi, my son is admitted to school of communication and his intended major is Communication Study right now. We talked about doing a double major or a minor/certificate, likely in other school like Weinberg or Kellogg. Is it easy to achieve this goal in Northwestern when he is a school of communication student?
The other major, minor or certificate he is interested are Economics, CS in Weinberg, Certificate of Managerial Analytic or Financial Economics.
Any info will be appreciated!

S is in Engg and doing Kellogg Certificate…so I do not see any issue w.r.t your son’s choices.