Okay so my sister was 15 years old when this guy he was 21 year old decided to date her he will get her drunk buy her alcohol take her out of school to motels they had intercourse and she endes up pregnant and he left her... so its been almost three years and I would like to know if she can still or my parents can still press charges on him for wjat he did?

It really depends on where you live as the laws on this vary by location.

Why weren't charges filed as soon as she got pregnant? This person is clearly a predator and I'm sure he has done it again in the 3 years since.

But as J_9 says, local laws determine whether the sex was even illegal (though it is likely it was) and whether a Statue of Limitations has past.

And why hasn't your sister, at least gone after him for child support?

Why did they not do something 3 years ago?

Why is it now that they want to do something?

Has she also filed for child support ?