Isopropyl alcohol is also know as rubbing alcohol, so you might check your local drug store / chemist shop [I am not sure what they are called in Pakistan, sorry]. It is a wood derived alcohol and not drinkable. It's main use in treating Bronze disease is in the final step to help remove any remaining water from the coin.
I prefer using a combination of sodium carbonate and sodium bi-carbonate to treat Bronze disease, it is effective and safe to work with.
Bruce