1. There is generally no "store" in the detention center, but if you have money, you can buy some daily necessities and food in the store (the price will of course be much more expensive than the market). As for the inside story, I can't explain it here.
2. What's going on in the detention center is what you said, "It's still dark". There is no pure "open air", and occasionally some violence is not uncommon.
If you want your brother to suffer less in it, it is a better way to send him some money by mail or directly to the detention center, even if there is nothing to sell in it, it can be used for other purposes.
Click on "User Profile" to find me.