UPDATE:
Thanks for all the support! Anyways, I found him!
After spending every night exploring the attic (my muscles are now toned from all the climbing, ha ha), I saw a small connected area that was towards the inside of the wall, and I was able to army-crawl inside. He was in there caught in a million wires/metal. He was extremely thirsty and seems a bit smaller than his brother, but he is alive!
Anyways, I took him to the veterinarian, and they said he'd probably be okay, but to take him in if he isn't acting back to normal within four days, because then they would like to do some more testing on the lungs and his system to check for damage, since it was correct about the insulator in the attic. I know because the person who told me was the person who put in, and specially got it to try to kill any animals that got in, including snakes.
THANK YOU EVERYONE FOR YOUR HELP!!!! I had never lost a snake before, and I honestly thought I was immune to the chances of losing one. However, once I saw that I had lost a snake to my gigantic attic that was made to kill snakes and be nearly impossible to walk around, I nearly fainted.
I now have safely taped up the whole reptile room so there is absolutely no where they can go.