She wanted him to remain useless and easy to control. Unfortunately, he just had to read her message which revealed a bit too much information. In that message, the sender was telling her that he has managed to find the identity of Simon's real father. What should he do with the man?
Only for the deceased to read that message, revealing a bit too much and putting her happiness and son's future at risk.
She knew that although the man was controllable, this was his pride and what if after he returns, he would make all the clan leaders gather and deal with her?
She couldn't have that, so she had him killed in an accident, and then using her son's rage towards the Frost clan to input the idea that it was Xander who killed him and no one else.
That was a way to temper her son. He shouldn't be able to control Gloria but be ruthless in his ways as well.
