Pregnant sister wants divorce and reimbursement for life and month

my sister got married on july 2017 and my sister is illiterate which we never told to our inlaws later after the marriage they found our that my sister doesn't know to cook food or to read and right so he started treating her ill, my brother in law is very angry person. day before yesterday we found out that he slapped my sister twice during period and when we asked him he said she never wakes up early or do any household chores. now we brought her to my house and found out that she is pregnant. we need divorce and or the other hand want to punish my brother inlaw. we think that if my sister will go back there might be threat to her life. so will it be wise ideas to get abortion in this case. my brother in law know that she is 2 weeks pregnant and he said us to do whatever you have to but think twice when i talked to him. he is very angry on ys as we have taken police at his home to bring our sister home. we didn't filed any fri till now. and i want full reimbursement for the marriage