Rewarded for my help

I live with my mother 43 and sister 21 and I'm 25, the reason my parents married as was pregnant with me. But the marriage didn't last our father after 10 years and died 5 years later in a work accident. So, we were struggling financially after the divorce and more after the death of our father. No payout by his employers as he wasn't on their payroll, just day labor and their lawyers got them out of any responsibility. We didn't have the money to fight them, so they got away with it. Anyway, I would help our old neighbor after school, he lived in an old house nothing flash and we thought he was like us struggling to get by. I worked a job on Saturday and the money I made I gave to my mother. Early last year the old neighbor passed away and we went to his funeral nothing flash and only the 3 of us there beside the minister and the funeral company people. We thought the government, or a charity had paid for the funeral. I had a job working at the supermarket and so did my mother and sister. Then I was approached by a man in a suit, and he asked if I was me and I said he then told me I was left everything by the old man. As he had no relatives and was thankful for my years of help. I didn't think I would get much but was told he own his house. But I had to go to the reading the will next day at the firm's offices. So, I had to make a change from morning start to afternoon start so not to lose money. My mother and sister were shocked by the news, but happy as I would own my own home and we wouldn't be renting anymore. But we didn't get our hopes up too far, we don't get lucky much and never anything big. I turned up and was shown into a large meeting with a large desk, like you see in movies where everyone talks about company business and things. I thought the lawyer would come tell what I was inheriting, and I'll sign a paper and that would be that. But 7 important people came in the head of the firm and all the partners as well. After they told me what I had inherited I almost fainted and I had to sit down for a time and was waiting for the catch there had to be a catch. No catch the old man was very rich and became a recluse after his wife died and he his children had no children of their own and had predeceased him. I had started helping at 11 and he liked my visits and after his last child died 3 years before he had made his heir. Never said a word about his wealth or family, of course the law firm was managing all his businesses and interests. Which included a major share the supermarket chain which owned by workplace. But the law firm wanted to know one thing, would I be making any changes, like replacing them. No, I said and signed another document to make that official. I was driven to the supermarket and took the day off and had my mother and sister finish for the day also. The lawyer who was with told the manager and he accepted we had the day off and might need 3 more staff. Similar effect on my mother and sister on their hearing of my inheritance. But as we took stock of everything, I said to them it was our inheritance no just mine. We stayed in the rental while the old man's house was fixed up and painted. None of us had driving licenses as we couldn't afford a car or the gas to run it before. But we knew how to drive, just didn't get licenses and now we didn't need a car. As we could call a limo if we required transport, but a taxi was our choice usually. We didn't have much in the way of close family, no grandparents or aunts, uncles or close cousins. In late November we moved into the renovated house and planned a big Christmas just the 3 of us, we overindulged and drank too much. As we weren't drinkers before we couldn't afford it either, getting very merry I'll call it on Christmas eve. all waking up Christmas morning naked in mother's bed and we had been fucking. No precautions taken my sister or mother on the pill either and yes, I'd fucked both. The result was a pregnant sister and not a pregnant mother as well, but we didn't keep fucking after Christmas eve. But I started to fuck my sister regularly after she was confirmed as pregnant. We also assumed mother was passed get pregnant and she also joined in. She wasn't, just hadn't gotten pregnant from our fucking on Christmas eve. My sister gave me a son and mother a sister/daughter last week. Due to both babies being born only months apart we pass them off as twins. Boy are usually bigger than girls, so nobody suspects they have separate mothers. My sister acts as my wife and mother as mother. Both breasts feed each child and we are quite happy with our new lifestyle. More children aren't out of the question, but only with my sister. Mother is getting fixed up as she calls it.