My friend had to have her baby delivered at 25 weeks because it wasnt growing and was at risk if not delivered. She only weighed in at 1lb something as well, although she was in hospital for a long time until she weighed a normal healthy newborn weight of 6lb she is perfectly fit and healthy like any other normal baby.
Your little boy will make it im certain, they are so strong despite being very small and only a few days/weeks old, its amazing how the human body works to fight especially when we are very young it works harder and is much more resilient than in our late teens/early twenties, when you would think it would be at its strongest.