[anonymously]

I would not hold off surgery if the vet is recommending it. If you have any doubts, consult a specialist as soon as possible.
I would feed the prescription food and stay away from supplements unless the vet approves. http://skeptvet.com/Blog/category/nutrition/

Be careful about taking a “homeopathic” approach to this condition. Natural does not mean benign and some supplements are not only ineffective but can cause harm.