So, Spike was all about killing Buffy. He could have easily gotten her taken care of with her mother involved. But I think he didn’t because he has a soft spot for mothers. What with the whole issue with his own mom and how he use to be with his mother when he was William I still think he respects them. Of course, the whole thing with one of the slayers being a mom and him killing her anyways, was an after thought. The kid wasn’t mentioned until later. Yeah, he likes moms.