I'm so sorry about Peeps. You did the best you could given the circumstances. Even if you had the money to pay for treatment, finding someone (knowledgeable or willing) to perform surgery on a chicken is a major undertaking.
I had a prolapsed hen a few years back and I tried everything I could to keep her intact--even took her to a vet who put a "purse string suture" in her vent. She wore that a few days and after I brought her home when her suture was removed, she prolapsed again. My neighbor put my hen down for me and DH buried her and said that Gabriella had "a mass or something" that came out after she died. The vet just didn't know what to look for, but he was the only one in my area that was even willing to look at my chicken.
I really understand your pain and grief. I hope your broken heart heals quickly.