High blood pressure after giving birth...???

My friend had her first baby 10 days ago, her baby was born at 35 weeks. My friend stayed in the hospital for a little longer because she had high blood pressure, feeling dizzy. Once she went back home, she could never fall asleep, had bad anxiety, today she had a blank stare and wasn’t talking. So, her husband got her back to the hospital now.

What can it be?