Thanks for the query.
The best way to prevent kidney
stones is to drink more fluids.. About 3.5l/day.
With regards to NEERI syrup we have no evidence in Allopathy. However Ayurvedic doctors use it quite often.
If you have an enlarged prostate
it's a good idea to see a urologist
who wil examine you and may advise further tests like PSA.
Hope this helps.