She may be experiencing a lot of stress and this is coming out in a negative way with mood swings. I assume this is a complete 180 from before she was pregnant?
I have seen more than one family member go completely insane in early pregnancy. In one persons case magnesium helped greatly because she had a hormonal imbalance. She was very violent and cruel like your describing and then her daughter was the same way 25 years later. Adding new hormonal surges to stress, can be overwhelming. It will probably pass as she enters the second trimester. Warning I have notices it seems to start up again in the third.
No worries! Many people read posts for a very long time after the original poster asked their question. Your insight can help the next person searching for help in this type of situation they are having-- so always good to comment. Thanks for trying to help!