We are so sorry that you are having this problem, and that you went through this situation.
Before we look into the possibility of this being a translation problem, can you please make sure that your brother in law, and your sister are associated properly to the family tree. This will make sure that they are identified properly in their relation to everyone else on the tree.
Please see the following post in our FAQ regarding associating yourself and other members of your site:
I have similar problems with Ukrainian names for relatives and some other expressions as well. Is it possible for me to take a look at the complete English-Ukrainian correlation table and point out the discrepancies? I would really appreciate that.