Insurance claim paid to beneficiary

My brother passed away in a vehicle accident where his ex-girlfriend (mother of his child) was the driver (she doesn't have a driver license and was under the influence). He had a life insurance policy where he made his daughter the beneficiary. In his will he requested that a testamentary trust to be established and to be managed by my two brothers until she is 21 years old. The police is still busy with the investigation so we havent received the final report. The ex-girlfriend phoned the insurance company requesting that the money should be paid to her because she is the guardian. The mother is unemployed, she drinks a lot also using drugs. What can we do to ensure the money is paid into the trust and not directly to her. She has criminal records, and also had an interdict against my brother, but she still called him to assist their whole family financially. We also want to get the child away from the mom but what can we do to ensure she doesnt get the money. She denies that she was the driver. But the insurance company wants to pay the money. Please indicate the way forward, how we can stop her from receiving the money.

Optional Information:
Province: Mpumulanga

Already Tried:
Phone a local lawyer, he said that the money will be paid to the guardian nothing that we can do.