Well, to put the thing in perspective for your son - my fist slam lasted 10 days and I have thrown approx 80 gallons of bleach in the pool, so you can tell him this is just the beginning.
My cya was higher than yours though (~90, so I had to maintain a FC at 30+).
The hard part in the process is to stay strong when the whole family starts to doubt the method and beg you to stop.
Next time you go to the store buy all the bleach from the shelf, that will save you some time.
Now I am throwing one gallon every 3 to 4 days to maintain my FC at the correct level and everyone is happy that the pool has never been that clean and easy to maintain.
Also : there is something wrong in your process, either the pool is way bigger than you think it is, or the test is not done properly, or the bleach is not fresh, because it should be easy to make the FC spike at 12...