My dear gentile friend gave birth very, very prematurely (at @ 5 months) to her due date. The female baby survived but is still dependent on a breathing tube and is still very weak and underweight. She just came out of the hospital @ 2 1/2 months ago and is now one. What prayer may I say?
I don't think there's any one recommended prayer, but Psalm 30 is a popular one to say for healing. It concludes "You turned my mourning to dancing", which is the outcome we all hope and pray for here.
Prayer is an organized form of speaking to God, but you can formulate your own prayers in your own words. There is actually an "organized time" for adding personal prayers at the end of the Amida (Shemone Esre) prayer that one says three times a day. If the baby already has a name, you should mention it.
If you prefer to rely on existing prayers, one traditional psalm said in times of trouble is Psalm 20
For the leader. A psalm of David.
May the LORD answer you in time of trouble, the name of Jacob’s God keep you safe.
May He send you help from the sanctuary, and sustain you from Zion.
May He receive the tokens of all your meal offerings, and approve your burnt offerings. Selah.
May He grant you your desire, and fulfill your every plan.
May we shout for joy in your victory, arrayed by standards in the name of our God.
May the LORD fulfill your every wish.
Now I know that the LORD will give victory to His anointed, will answer him from
His heavenly sanctuary with the mighty victories of His right arm.
They [call] on chariots, they [call] on horses, but we call on the name of the LORD our God.
They collapse and lie fallen, but we rally and gather strength. O LORD, grant victory! May the King answer us when we call.