Depend on how large the "hole" is. My son (twin 1) is a preemie, born at 27 week. He had his PDA closed by surgery. He needed surgery because the "hole" is large. My other son (twin 2) also a preemie, also had PDA, but it is closed on its own after a round of medication. I am not sure about PDA on full term baby, but even if it is worst case that your baby needs surgery, PDA ligation is not as scary as you thought, it is usually completed within 1.5 hr, including prep time. As far as I know (as in my son's case), this surgery is only performed at Queen Mary.
Hi Yung2224, as my boy was born 3 months early and had PDA ligation at 1.5 month old, he was still too small to suck the bottle at that time (he was tube feed). But I would say if surgery is needed, don't worry too much, it sounds scary at the first place, but the doctors who perform this surgery (those at QM) are experienced. Also when they did the operation on my son, my son was less than 3.5 pounds, it is amazing that they could do it on such a small baby. As your son is full term and heavier, the risk of the operation is even lower.
My son did get better gradually after the surgery, like one of the nurses said, the surgery just corrected the circulation of blood. It is just necessary! But every baby is different, some may take a few days to recover, some may take longer. I hope your son will soon take the bottle, but for now no worry as the hospital will monitor your son's body weight, they will give him nutrition via IV of necessary.
One thing is that they will choose a right time to do the surgery, i,e., when the baby is at a better situation. In my son's case, the surgery was postponed because my son had fever / had infection. I guess they may wait until your baby is recovered from the pneumonia, but the doctors should know the best, just meet the doctor and let them explain to you the situation in details. Sometimes you just need to push the doctors a bit to get things done.
Let me know if you need more info about the surgery. Don't worry too much, have more rest, your baby needs you to take care of him after he is discharged from the hospital.