I wish I could say that severe mitral valve regurgitation repairs itself, but unfortunately it does not. There is no diet to cure what she has. In your daughter-in-laws case, was she ever diagnosed with a mitral valve prolapse or was this just found all of a sudden? I have moderate to severe regurgitation and it's been a progression over a number of years. It is basically a degenerative disease and usually once at the severe level, starts to have different effects on the heart and a repair is usually recommended. Has a doctor done a complete echo on her and come up with a plan for her? It breaks my heart that she has been through so much in the past. What symptoms is she experiencing from the regurgitation? Please make sure that she gets herself a very good cardiologist
Sorry to hear of your daugther-in-law's medical condition. Sometimes there is relief to mitral valve regurgitation if it is related to ischemic heart enlargement or stressful event(s) effecting the heart. The orifice of the valve becomes maladjusted due to the enlargement and this causes regurgitation. Also, the cords that tether the leaflets to heart muscle walls can become elongated.
About 6 years ago, I had an enlarged left ventricle with moderate to severe MVR, and I was told sometimes it is helpful to the valves if successful treatment reduces LV enlargement. Treatment reduced (reverse remodel) my the left ventricle to normal size but that did not, it seems, help the MVR. With all your in-law has medically experienced may have placed an overload of stress on the heart that caused an enlargement, and with adequate treatment and some time to heal may be helpful.
Hope this provides some insight. Thanks for sharing, and if you have any followup questions you are welcome to respond. Take care.