Apparently he had ben mad about something and he being him took it out on the warmest person who happens to be his demon caretaker. Micheal knows Ethan loved the woman as much he loved his own mother and he was more than hurt when he found out his fangs were the deadly posion to her. As he was still young, they had tried giving her his blood hoping it would cure her but none worked. He sat by her bed probably blaming himself all through the day as she experienced pain and finally gave up her life the following morning. It was a sad and quiet morning.
No. It wasn't that they were sad she had passed on, they were mostly scared that they wouldn't be safe around Ethan anymore. To be honest Micheal knew that was where it all began to change. When they found out what poison he ahd in him. Ethan knew what he had over them not to say he has always been stronger. Despite being the third to the youngest.
