I guess someone may not be pregnant. She claimed she was pregnant when you were pregnant - in order not to be looked down ma.
She is so $$宫心计. She might be scared of that you would have all the $$ benefits from your 99. Hence, she said she was also pregnant at the time you were pregnant.
If so, she would claim 小产 later because she is forced to move out of the property. Anyway, it wont bother you, no matter what your 99 or 細嫂 would say later.
After following the development, your 細嫂 is not alone. Your brother in law is even more... asking your hubby to pay the banquet for him - 厚颜无耻.