If he really wanted to let Lily live, he would have stunned her, or he would moved to cast the Killing Curse on the crib without harming her.
That’s true enough.
But I don’t think keeping his deal with Snape required making sure that Lily lived, it required giving her a chance. You say it was a crappy chance. Maybe so. But this was a concession on Voldemort’s part, and expecting a Dark Lord to do more than the letter of an agreement is asking a bit much.
He gave her a slight chance of living with the guilt of having scarified her son, which sounds more like torture than generosity to me.
If he really wanted to let Lily live, he would have stunned her, or he would moved to cast the Killing Curse on the crib without harming her.
Asking her to voluntarily stop protecting her child is sadism, not a real attempt at sparring her life.
That’s true enough.
But I don’t think keeping his deal with Snape required making sure that Lily lived, it required giving her a chance. You say it was a crappy chance. Maybe so. But this was a concession on Voldemort’s part, and expecting a Dark Lord to do more than the letter of an agreement is asking a bit much.