Thanks for the help guys

I have good news!! I found the balloon last night in the litter box and he is out of danger.
We first gave him 1 tsp peroxide the day it happened and he did not throw it up. Then we were told to give him a piece of a pepsid to ease his tummy from the peroxide. I gave him some butter too just to help things slide smoothly lol. Thankfully he had no trouble passing it.
My whole family all cheered over the scooped up balloon poop while our two kitties looked at us like we had lost our minds! I'm just glad the wait is over and I can finally stop worrying about him.