Sons Father In College But No Job

I didn't end up having a healthy relationship after my son was born so i moved out of the apartment i had with my sons father. Moved home and tried getting along with him which is ok here and there. I work 40+ hours a week and im a full time college student. Financially i am barely making ends meet. His family is somewhat wealthy and i dont understand why i dont get the help i need from him.

Its like pulling teeth for him to pay half of babysitting which 8 times out of 10 never ends up happening. I can count of my fingers how many times i have received something from him and my son is going to be 3 in august. Also he hasn't even signed the birth certificate. i have been trying to give him the benefit of the doubt because he is a great father when he is with our son i can not deny that but that doesn't take care of my sons financial needs.