If Anna actually believed Howard killed Daniel you can be sure he kept her over-medicated and mellow and totally dependent on him.
It's another reason that Anna wouldn't commit suicide. She knows that Howard was a sh**-a** father and REALLY didn't care for this new addition. The will says if Daniel and Anna died, he gets it all. Dannie Lynn REALLY complicated things but there was no talking her into an abortion. (I'll bet he tried). So score one for Anna. LIFE meant a lot to her.
AbsoANNAlutely.