As a nurse then, you learn just what each person needs on a weekly/daily/monthly basis. Your pool will be the same. Add x amount chlorine daily, add x amount muric acid weekly or as needed, run CYA test monthly.
As for vacation....your friend can just add a set amount of chlorine each day. Show them that test and have them call you daily with that reading. Put the info in the calculater and tell them to add X amount bleach.