"Of course not. She was a homicidal maniac by the time I met her and absolutely insane by the time she escaped from Azkaban. All I know is that she's not insane right now - I've been inside her mind, I am confident she's not - and that exposure to certain of our former associates can't be good toward keeping her that way."
Severus recognised the desire to change the subject, but Lucius might have insight that would help him in his actual purpose.
"She tried to destroy the village or something close to it shortly before you arrived. My hope is to become close enough to her to be able to prevent that sort of disaster if and when her rational mind breaks and do what I can to prevent the rupture. Do you know? What or when she changed? I didn't know her well enough during the first war; she's too much older than I. I almost wonder if it was too much exposure to the Cruciatus Curse or our former Lord's brand of mental violation with Legilimency that put her over the edge."
Besides, the only other thing he had to tell Lucius that he might consider 'newsworthy' was his budding relationship with Lorcan, and he really didn't want to go there. Whether Lucius would be disgusted to learn that Severus was a pouf or that his new companion was a half-vampire, the reaction was sure to be unpleasant.