I've Psoriasis (which is a skin condition) in addition to diabetes and I consume goat's milk for healing psoriasis. If you're allergic to cow's milk or lactose intolerant or have additional problems like leakygut/psoriasis/eczema caused by casein intolerance, goat's milk helps. Otherwise, i dont think it helps.
I've not seen my diabetes improve or degrade with goat's milk. However, it relieves me from the acidity/skin problems that would occur with cow's milk.
Goat's milk costs more as well. Also, goat's milk lacks vit-D unlike cow's milk and if u take goat's milk, you need to ensure you dont suffer from vit-d deficiency