IRS refund for deceased taxpayer

I was caregiver & had all POA's for my friend. He passed away on April 1, 2024. I filed his 2022 personal tax return in May, 2024. The IRS sent a notice shortly thereafter, saying they needed more information because their records indicated the taxpayer was deceased. As instructed, I filled out a form 1310 and submitted it, along with the certified death certificate. On the 1310, I checked box "C", certifying that I was NOT court appointed & completed Part II. As of August 5, 2024 they are still processing that return. They have had everything they asked for for 3 months. It's also confusing as to why a 1310 had to be filed at all. The return was for 2022 and the taxpayer didn't die until 2024. How should I proceed? The phone #'s for customer service put me thru to people who have no idea how to help me with this.