Hello and welcome to Share. Congratulations on the birth of your son. I'm sorry that he came so early and that he is struggling with his lungs.
I had a 25 week preemie with chronic lung as well. He didn't outgrow it until he was almost 3 years old. With that being said, he did get stronger and went home after 99 days in the NICU. He always struggled with breathing and went home on oxygen for another 3.5 months. After my son had the PDA surgery (clamp in the heart) his lungs collapsed and he was really struggling and was on the oscillator. He eventually worked through it though. He progressed slowly and we just had to be patient with him. They really are on their own schedule and sometimes take longer than we'd want or expect.
He is now almost 5 years old and doing great. We use inhalers when he gets a bad cough from a cold and he's more susceptible to get pneumonia quickly from a common cold than other kids. Other than that, almost no one knows he was a preemie. Feel free to ask any questions or vent to us. We are here!