Blood clot on finger. Any further.

My mom is diabetic n it's normal. Suddenly she has got blood clots on her hands ring and index finger. The finger has become blue black and she is in acute pain since 1.5 months . Till now she has visited 2 general physician, 1 dermatologist n also diabetic specialist and no one is able to point out the exact problems of clot and it's cure. She was also checked with oxygen level in her finger tissue and that seems to be bad for those fingers. She was given Enoxatroy 60mg injections for 10 days by the doctor for blood thinning but still no remedy. The doctor have scared me by saying it may lead to Gangrene and therefore I ask here which specialist should I take her to and wat would be ideal treatment for such clots on finger..other than diabetes and clot on hand she doesn't have any other issues until now. Please guide me with the right measures as I do not want anybody to experiment with her problems any further.