As salaam wa alaikum, my mother is a very pious lady she recites quraan daily alhamdulillah, recently an ayurvedic doctor suggested treated cow's urine as a medicine foe a chronic disease she is suffering from... though she does not know about this medicine, I'm reluctant to give her this as I feel how can Allah subhan wa taal provide the source of shifa in such a filth... and moreover I'll be cheating on her and on my imaan as well. Please suggest.

In any language it is filth (treated with what !). Don't give it to her.

Cow urine is the basis for heart medicines (but I haven't read about this in years, perhaps because of the gross factor). Ghandi drank his own urine, untreated. Many do.
Urine Therapy - The advantages of taking the piss - Drinking Your Own Urine (http://www.fruitnut.net/HTML/201_Article_Urine.htm)

This is not about Allah, but a son doing his research, and providing good health choices for his mother. So start studying this thing she asks, and other alternatives from other doctors. Is he the only doctor available? If not seek a second or THIRD opinion.

If he is then you have few options in this. What does she suffer from?