My sister-in-law is locked up in my house, okay?

Sister-in-law's confinement at your house is good for you. Reason:

1, your sister-in-law is your brother's wife, so you are all family, and family actually has no influence. He is your younger brother, so you must trust your family and treat you as your own relatives and brothers, so it doesn't matter;

It is actually a very happy thing that he is locked up in your house and gives birth to a child in your house. You should cherish this time and it won't bring any bad consequences to your family, so you don't need to worry.