I have to say I agree with you. Regardless of how this all turns out, the woman is still dead. However, he was trying to kill himself and she got in the way when she was trying to stop him. I don't think anyone would have figured the bullet would go all the way through (maybe there was nothing in that skull of his to slow it down) and hit the woman. 
I would honestly be surprised if he was convicted of second-degree murder. If what was said was true and he tried to kill himself, gun was pointed at him, not her, she tried to stop him, bullet goes through his head as intended but exits and hits her, her death seems more like an accident.