what should I do?

So, my child's father left me unexpectedly over a month ago. He now is with another girl and doesn't speak to me or help me in any way.. his mom claims to be here but at first she tried to force me into adoption. I see it as, if she cares she would tell him to stop being a little b**** and help me with what he can, but she doesn't. She lets him run around doing god knows what. If they do this throughout my whole pregnancy, should I let them be in my child's life or have any say? It's just really wrong to me.