Mother Attacked By Evicted Squatters

Location: California

My family recently took possession of a property on Jan 30 and removed the squatters and all their property. We asked the mailman to stop all service at that address and to return ALL mail being delivered there. Last night at 7pm a woman who lived at that house prior to being evicted showed up with a “demand letter” claiming my family stole her mail and packages. In the letter she’s threatening to file a police report, mail fraud, and small claims court. My mother told her everything was returned to sender and to talk to the post office. The woman started mouthing off so my mother said get off my property or I’m calling the police. The house is currently under renovation so there’s about 6+ no trespassing signs on the property. The woman swung on my mother so my mom hit her back. My mom is 68 while the other woman is much younger. Our ring picked up the audio but not the actual attack. My mom had a fractured leg and is currently in the hospital. She’ll have to have surgery within the next couple of days. The police, fire truck, and ambulance came. The police gave both my mom and the woman a ticket for battery even though she came on our property, hit first, and had a knife on her they later found. After I gave my statement to the police I saw the woman standing around waiting to talk to them. At this point what is legally the best thing to do? She’ll have to appear in court in May for the battery charge.