I like this. It shows the real dilemma the children of the Death Eaters had. Even ones that wanted to do the right thing were faced with having to fight their own families. Even if what he was doing was wrong and evil, Lucius was still Draco's father. You did a good job of portraying the angst he had to feel, having made a very hard choice.
Only a couple things to suggest to you. One, I would have liked it a bit better if Draco had made the same choice with his eyes open, i.e. faced the Death Eater, knowing full well from the distinctive mask that it was his own father, but determined to do what was right. While your depiction was good, this would have shown more strength of character. Two, since you recognize that you have aspects of writing that you are less that stellar at, you should get a Beta reader. They can help you with grammar and spelling, and can even help reword a scene.
Overall, though, it was a nice fic. A bit morbid, but nice.