Mother's breakdown

My father ignored my mother (41) most of the time. Their marriage was arranged, and he resented that. Had me, and after that, he ignored her as much as he could. Depending on his parents' money, he had no other choice. My mother coped by focusing on me, and then I went to college. Leaving her alone, my mother, according to my father, had a mental breakdown, and he wanted her put away. Fortunately, I came home on a break, and my mother improved a great deal. Causing my father's plans to have my mother put away to be cancelled. My grandmother realized she had always been very close to me, and suggested she move closer to me during my college terms. An apartment was leased, and I would stay with my mother there. Away from most of the extended family, my mother focused on me. Then one night she joined me in my bed. No sex, just wanted to be near me. After that, I slept in her bed every night, and we started a sexual relationship. My father visited, but stayed in a hotel, only came because his mother had asked when he was going to visit his wife. It turned out to be very convenient, as I had messed up and left my sperm inside my mother. My father paid cash for his hotel room so his mother wouldn't know he had actually stayed with his wife. After his brief visit, he went off to enjoy himself. He overindulged as usual and had his first stroke. Caused by drugs and alcohol is what I personally believe. While in the hospital, he had another massive stroke and passed away. After the funeral, we were still living together and fucking. My mother tested positive for pregnancy. Of course, it was a surprise to almost everyone except me. My grandmother did some calculations and decided that it matched her late son's visit perfectly. I wasn't going to say anything different. My mother said nothing as she feared she would be taken away from me. With the birth of my sister/daughter, my mother had her tubes tied. So, no more accidents can happen.