Pregnant Sister Update

Cassie is pregnant again, this time to me we messed up last year in August. But as we live together still, and she is a stay-at-home mother with her daughter. I've been promoted and was lucky in starting an affair with my sister. As my supervisor left for an interstate position five months after birth of my niece. My sister acts as my wife, as we have bought a house together, only our mother knows who the father of her forthcoming grandson is. Our father passed away before we messed up. Our mother 50 is selling up and plans to live with us, plans on using her home's sale money to pay off out loan.