Hi mum, I wish your baby good health. I am sharing an article with you. It might be helpful. https://kidshealth.org/en/parents/patent-ductus-arteriosus.html#:~:text=Patent%20ductus%20arteriosus%20(PDA)%20is,to%20flow%20to%20the%20lungs.
If doc say it will dissolve by itself than it should be ok. If you still worried than perhaps u can go to another private hospital and get 2nd opinion. At least u hv piece of mind