Serenity, I know of a doula that I think may live near you that would probably be more than happy to help you either during the birth or looking after your son. I know there are also doulas that are part of a 'heart network' that will help for free. Do you want me to track down some details for you?
I agree that it's probably best for him to leave for now, you've got too much going on right now to worry about him as well. I know you don't like his parents but do you trust them enough to just help you with your DS during this time?