Letting cakes dry out.

In those 2 weeks the cakes would almost certainly have flushed again. Dunking isn't absolutely necessary, but help rehydrate the cake between flushes to potentially increase yield.

Have your brother dunk them for you. It isn't all that hard.

No i mean, the cakes are going to be sitting in the closet for two weeks without anything being done to them after he harvests it. If i let the cakes just sit there will they go bad? Or can i just drunk "rehydrate" them as soon as i get back to continue the flushes?

Not sure if anyone has even ever tried this before...

I wouldn't trust them that long in a stuffy closet without any airflow. Once I started having success with bulk I still had a bunch of jars (like 30) in various stages of growth. They stay for awhile in jars, but once I put them in fruiting a lot of them would end up contaminating after the first flush if you negect them. If they aren't contaminated by then, you can try I don't see why the mycelium wouldn't bounce back, but I have a feeling you are going to come home to cakes with a bunch of aborts and covered in trich or some other nastiness.

Dried mycelium will simply die (there is a rumor however of absolutely dry mycelium being crushed and sprinkled on agar and growth ocurring). The myclium survives behind the dried stuff - as the dry acts as a moisture barrier. It is surprising how long it takes for mycelium to die throughout the substrate. You will certainly get a diminished yield but they most likely will survive. Sonar encountered the truth however, when that mycelium is damaged it's contam resistant properties are compromised. I wouldn't "dunk" them afterward but simply put them in a humidified environment.