I didn't see your post yesterday mroll, I'm sorry.

Let me see if I understand: You are adding 3 oz dichlor every night after testing and every evening when you test your FC is 3. You are leaving Friday, July 20. If this is not true, tell me.

I recommend you keep dosing 3oz of dichlor a night after measuring FC, CC and pH.
If you read more than 4ppm FC, dose 2oz dichlor instead of 3oz.
Add Borax if pH gets below 7.2.

By next Thursday, you should have about 3-1/2lbs of dichlor in the pool with a calculated CYA of 40ppm.
Adjust pH to 7.4-7.6 before turning the pool over to your son.

While you're away, have your son do this every afternoon:
Test pool water with OTO.
If OTO shows 3ppm or less, add 6 Cups plain 6% bleach.
If OTO shows more than 3ppm, add 3 Cups bleach.
If your son has a pool party, add 8 Cups bleach before the party, test OTO ASAP after the party and add 3 Cups of bleach if OTO reads under 3ppm, repeat OTO test and 3 Cups bleach every 1/2 hour until OTO reads above 5ppm.
Have a great trip and don't worry about the pool.
Run a full set of tests when you return.

Keep us updated until you leave.