What should I do?

So I am 19 years old and about 16 weeks pregnant and hid it from my parents for the first three months. Anyways, they are perfectly fine with it, however, they have been insisting that we tell his parents. I agree that they should know but they are not exactly the most calm people. They have forced him in the past to leave me for ridiculous reasons and threatened to stop paying for his schooling if we got engaged or if he got me pregnant both of which happened. To get to my point my parents are pressuring him to tell his family all while he is pretending like we’re not having a baby.

He’s going off and purchasing tickets to go to some festival with his friend and now trying to go to another one in Germany. The first one during my anatomy scan and the second one during my birthday, days he should be spending with me and our child.. He also should be getting a job as I work part time and go to school full time but he has made no efforts towards that either. My question is if I should just tell his parents for him, post it online so if they freak out they expose their true selves, or should I just walk away from him at this point because he’s showing no initiative to be there for his child? I love this boy with all of my heart but my baby is the most important thing. I’m so worried about what to do, any advice helps.