That would be the best option. Would be a bummer to go back to square one when you get back. Main goal for those few days is to not slip below your target FC for your CYA (you are at CYA 40, right? So FC should not get below 5ppm). If you still fail the last OCLT before you leave, then ideally your dad kept it as close as possible to SLAM, but main goal is to not undo what you have achieved so far and to keep it simple for your dad. And as long as your FC stays above target-FC, you should be OK when you get back.
You currently have 1.5ppm loss over night (over 10 hours?), that is all due to algae. Over 24h that would be a total loss due to algae of about 3.6ppm. During the day, you will have additional losses due to UV. How much, depends on amount of sunshine, temperature, CYA-level and FC-level. It will probably be about 2-3ppm per day, i.a. about 5ppm total. So, if the over night loss stays where it is, your dad will probably have to add about 110-120 oz of 12.5% bleach per day. Does that match roughly what you were adding recently?
Let's hope that you pass the next OCLT, then you'd only have to deal with UV daytime losses.
Could you post the results and times of your FC-tests and how much chlorine you were adding over the last one or two days? From there we should be able to extract a best guess how much chlorine to add.