I would like to think his Mum was still alive unless Tobias beat her to death But Witches and Wizards live to a ripe old age.

I would not be surprised that Eileen may have meet her death under Tobias' fists. And that Severus killed his father.

At the same time, Tobias may have just died out of his alcohol addiction and Eileen is alive but living somewhere else than in Spinner's End, maybe back to her parents' home.

Who knows ?

keladz, no they don't. They die of diseases just like Muggles do; Lucius Malfoy's father, Abraxas died of Dragon Pox. ;)

I have felt for quite some time that Tobias murdered Eileen. Tobias probably drank himself to death.

Maybe this is some of the information JKR has been "hoarding for years", and we'll find out via Pottermore.

I keep thinking that maybe his mother was taken by some disease.....maybe part of what lead to his intense interest in the dark arts as a way to help her if nothing else muggle or magical could be found...?

Now, father, well, father I feel was someone who wandered in and out of his life and one day maybe just never came back....maybe he died in some alley somewhere, maybe Severus found him and threatened him, or maybe Lucius did and that lead to Severus' original loyalty....who knows.

But I've always felt that parental relationship led to some of Severus' interest in the Dark Arts.

(Nature vs Nurture is a big debate with me sometimes...LOL)

I've always imagined Snape's father being fond of the drink so I could see him insisting on getting behind the wheel while drunk and crashing the car with Snape's mum in the passenger seat

or car

I think that his mother was murdered by Tobias and in revenge Snape killed his father.