My 83 Year Old Mother-in-law Suffers From Constant Burping. This

My 83 year old mother-in-law suffers from constant burping. This was brought on by the aftermath of surgery for bowel cancer. This has become embarrassing for her and she has now become isolated and refuses to leave the home. Her doctors are baffled by this as pressing any part of her body bring on a bout of belching.
We would welcome your suggestion to relieve this symptom.