The blood type issue is…well, just unusual. From my understanding, and with opinions from two friends who are physicians (one is a hematologist) blood types don’t change spontaneously. There is ongoing research for potentially change blood types but nothing available now. It can and frequently does happen with a bone marrow transplant. So your daughter’s changing blood type, without SCT/BMT, is certainly an anomaly.
And actually, a bone marrow transplant may be an option for your daughter’s medical condition.

But again, from my understanding, blood cancers and infections don’t cause a change in blood type. They can alter the shape and health of blood cells or alter the production rate of blood cells but not change the blood type.

I hope you’re able to find treatment for your daughter. At this time blood transfusions are one of the key factors in helping her stay healthy and gain strength. Have you given any more thought to coming to the US to have her examined and a second opinion?