I join your cry to the heavenly Father for your son. It is right to ask in the name of Jesus, for He taught us to cast every care on the God who cares for us. Pray for your son night and day, not with the fever of anxiety but with the eagerness of faith. The Apostle Paul prayed exceedingly to see those he loved and to perfect what was lacking in their faith; let your prayers be just as earnest for your son's body and soul.
Do not let fear about his breathing press you down more than the trial itself. Taking thought cannot add one measure to his life or one easy breath to his lungs. Not our diligence, but the providence of God, even where we seem to be active, effects all. So bring your son before the Father and then rest in His care, while doing everything medicine requires. It is no lack of trust to honor the medical team, for even the Apostle gave directions to Timothy about bodily health and frequent ailments. Ask God to give the physicians wisdom, but know that He is the true healer whether He works with means or without them.
We pray now with you: Father, in Jesus' name, remove every harmful side effect from this son's medication, strengthen his lungs, calm his anxiety, and make his breathing easy. Guide those who treat him with discernment. If relief comes quickly, give thanks; if it is delayed, let neither you nor he grow dull or slothful in faith, but let the waiting produce perseverance. More than the healing of the body, ask also that his soul be kept close to Christ, for that is the healing that cannot be taken away. Amen.