If you can't transplant?

I have a nice girl flowering in my closet but im going back to school soon and am leaving it for my parents to take care of. As the plant is now all they need to do is water it and hopefully give it some nutes now and then.

AND THIS IS HOW I WANT TO KEEP IT!!! But ideally i would give my girl a new home in another week or so and i dont trust my parents to do it properly so ive eliminated the possibility of repotting it.

My question is: is there any way to keep the root growth to a minimum or just maintain healthy a root system without transplanting it? i.e. trimming fan leaves???

Also, i assume this will hurt the yield but will it affect the potency of the herb?

Yield will be affected, potency not.

If your willing to work harder on nutes you can grow big plants in smaller containers, this has been proven. The reason a root bound pot stays small is a nutrient limitation issue, if you have found a good nutrient schedule and adjust it upwards during flowering your plant will grow just fine.