My Brother

I've a brother 27 and a sister 29 and then there's me 31 the oldest married 2 children. My sister is also married and has 1 child so far. My brother doesn't seem to date or show any interest in women at all. So, I and the family were totally shocked when he told he was getting married, not engaged as would usually be announced first. But straight to marriage he was marrying the daughter of a former close business friend of my father, who sadly passed away in 2020. The daughter 20 the only child of father's late friend was pregnant to my brother and was the prime reason for the quick marriage. His soon to be mother-in-law 38 was always with them and only later I realized she had started wearing loose clothing and not the tight body-hugging clothes she usually wore. After the marriage my brother lived with his mother-in-law and new wife. Following the news my soon to be sister-in-law was already pregnant came the news she was having twins. No others in the family took note but I did, something didn't add up in my mind. Also, they just happened to overseas for the birth of the twins a boy and a girl. Some distance relative of the mother-in-law never mention before was the reason given. So, a month after the birth they were back home, and I noticed the babies were different sizes. But my wife said baby girls are always smaller than boys. Finally, I cornered my brother alone and asked him to spill the beans. He did yes, the babies weren't twins, he had gotten the mother pregnant along with the daughter. Having started an affair with the mother and the daughter joined later. Making a mistake with mother she got pregnant and after no precautions were taken with daughter, and she got pregnant rather quickly. Thus, leading to story of twins and quick marriage. My new nephew was with his mother-in-law and my new niece was with his wife and the oversea trip was to have the children out of sight of relatives and friends. I'd given my word not to tell the family, but not that I wouldn't write about it on an erotic story. My brother had been fucking his now mother-in-law for years and kept out of sight of everyone. Her late husband wasn't well and unable to perform, and my brother took his place. The daughter was icing on the cake.