Yes, UNTIL she figured out that HKS offed her son. For all we know, she had someone hire a private investigator look into Daniels death. We know she had the private autopsy done. Maybe she asked Wecht to get a PI involved too. Or she just put two and two together in one of her sober moments.
If Anna actually believed Howard killed Daniel you can be sure he kept her over-medicated and mellow and totally dependent on him.