Are there any non-surgical treatments available for congenital diaphragmatic hernias?

No: These type of hernias can be very serious. They are surgical problems. Anyone who suggests otherwise is wrong. There is an old saying which goes "the treatment of a surgical disease is surgery". This applies here.

Requires surgery: Surgery is required to treat congenital diaphragmatic hernias. The surgery occurs either through a scope that the surgeon inserts into the body or after an incision is made in order for the surgeon to visualize the area to repair. A few highly specialized centers may offer experimental fetal interventions. One example of this is balloon tracheal occlusion.