Complaint in CAW cell

My sister in law has made complaint against in CAW cell in Delhi, but we currently residing in Kerala but my brother is an NRI, and won't able to come to India till February due to visa issues, and we have received a letter asking him to appear before CAW office by this month-end.if we ignore this letter will it be a problem for him, as before it was agreed for mutual divorce but due to visa issues he can't come so they have made a complaint .So what will be the next course of action by CAW cell.