don't know what to do

So me and my bf are gonna have a baby soon but I'm not sure what to do my parents don't know me and my bf are dating but his do. We don't wanna tell them we are together until he comes back from helping his sick mom. I'm also not sure how to tell my parents about us being pregnat. He's 19 and I'm 16 Ik they will be disappointed Bc my sister was also a teen mom. I don't want them to send him to jail. He's said he will take responsibility for me and the baby. He has a apartment for us to live in and a car to drive and also a job. We want to get married and he said if he needs to now to show them he will always be there for me and the baby he will. What should we do/tell my parents?? Please give advice!!