do it when Amma is out of the house or find a battery shop you trust or know, give him a gallon of pure distilled and a new plastic bucket, pay him for his acid and let him mix it there, make it a little strong that you can water it down at home or his shop when cooled. Correct the SG to 1.270 and fill the battery, install charger unit and do the recommended life start charge of the battery, once done and passes all tests put into service.
If this mixture was ready available in the market we would not have such early failures of batteries, There is a brand of Pyro of Lahore I guess, people have had good experience with it, try finding it in Karachi.