Need advice and help

My sister is 21 and I'm 20. She just had a baby. My uncle and aunt are fostering him for now but are not willing to adopt. I am worried that if he gets adopted by someone else he may be mistreated. I also worried that I may never see him again. However, id hes adopted by someone who loves him and has the means to take care of him i would be so happy. I want him to go to a good family. I'm not in a place to adopt him at this time, and my boyfriend is against ever adopting him. Can i somehow be more involved in his life? Can i be sure that he goes to good people? How do i do this, how am i supposed to feel? What should i do? This is all so crazy.. i just need to talk to someone that actually knows something about adoption and fostering because i dont know anyone.