I was wondering the consulate will think if we sponsor for my sister-inlaw school?

How do you sponsor a person who is applying for a student visa? I wouldn't think they would need a sponsor, and I wouldn't think the consulate would think there is any relationship between your visa journey and hers, if that's what you mean.

it's the money part. She dosen't have enough money to save up for school.

She would need to show that she had adequate resources, as far as I am aware there is no restriction where they come from if you are feeling that generous.

It is a non immigrant visa, she needs to show non immigrant intent as well.

Tricky part is that she needs to show/convince Consular officer that she has strong tie to her home country, and will be back to home country after gruaduation.
Since you support financial portion, CO may think she may come to U.S. and stay with you.
But in other words, if she can convince CO that she will be back to home country after study, she may get it approved.
It's up to CO's mind at Interview day.