1. If a lawyer has appeared for your wife then he must have been engaged by her.
2. If your brother's wife continues to remain absent from the court on the dates appointed for hearing the court will eventually dismiss her case.
3. She can file a case for domestic violence against your brother and his family members. This apart, she can also sue your brother for maintenance. She may also file a criminal case for assault, etc against your brother and family members.
4. If further criminal charges are slapped then file for anticipatory bail to escape your arrest.